• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.2
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• pp.449-456
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• 2015

Recently, information security of IoT(Internet of Things) have been increasing to interest and many research groups have been studying for cryptographic algorithms, which are suitable for IoT environment. LEA(Lightweight Encryption Algorithm) developed by NSRI(National Security Research Institute) is commensurate with IoT. In this paper, we propose two first-order Correlation Power Analysis(CPA) attacks for LEA and experimentally demonstrate our attacks. Additionally, we suggest the mask countermeasure for LEA defeating our attacks. In order to estimate efficiency for the masked LEA, its operation cost is compared to operation time of masked AES.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.5
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• pp.65-72
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• 2007

In this paper, we investigate the several different types of higher-order differential side channel analysis (DSCA) attacks. We present that some of exiting higher-order DSCA attacks have some practical problem applying to two masked intermediate values being parallel processed. In order to solve this problem we propose a new higher-order DSCA attack using an efficient and simple preprocessing function. Using the proposed preprocessing function we clearly show that 2nd-order DSCA attacks are still a practical threat fur masked hardware implementations.

• Korean Journal of Environment and Ecology
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• v.27 no.2
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• pp.230-240
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• 2013

The fish fauna and population characteristics of Zacco platypus at the 9 habitat types in the Hongcheon River were investigated from August, 2009 to April, 2010. The collected species during the surveyed period were 21 species belong to 6 families. Korea endemic species were Acheilognathus signifer, Microphysogobio longidorsalis, Pseudopungtungia tenuicorpa, Squalidus gracilis majimae, Zacco koreanus, Iksookimia koreensis, Silurus microdorsalis, Liobagrus andersoni, Coreoperca herzi, Odontobuitis interrupta, and Odontobuitis platycephala which showed 61.9% ratio of total species. Dominant species was Z. koreanus, and subdominant species was Z. platypus. Dominant species according to habitat types were Z. platypus(in side channel, substrate type pool, and riffle), Z. koreanus(channel connected pool, run, meander type pool, and rock type pool), M. yaluensis( dam type pool ) and Rhynchocypris oxycephalus(channel unconnected pool). Length-weight relationship in the population of Z. platypus was 3.27 in regression coefficient(b). Principal component analysis was classified as 2 groups. Bray-curtis cluster analysis indicated that the channel connected pool and meander type pool showed the most similar values(66.2%), whereas side channel and channel unconnected pool exhibited the most distance values(32.1%).

• Journal of Wetlands Research
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• v.16 no.3
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• pp.303-313
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• 2014

The spatial distribution characteristic of fish community were investigated at the 10 habitat types in the Nonsan stream from August, 2008 to June, 2009. The collected species during the surveyed period were 26 species belong to 6 families. Korean endemic species were Sarcocheilichthys nigripinnis morii, Squalidus japonicus coreanus, Hemiculter eigenmanni, Pseudobagrus koreanus, and Odontobutis interrupta which showed 19.2% ratio of total species. Dominant species was Zacco platypus, and subdominant species was Tridentiger brevispinis. Dominant species according to habitat types were Micropterus salmoides(substrate type pool and rock type pool), Lepomis macrochirus(channel connected pool and channel unconnected pool/abandoned type pool), T. brevispinis(channel unconnected pool/overflow type and run) and Z. platypus(riffle, meander type pool, side channel, and dam type pool). As a results of community analysis in side channel, diversity index showed relatively high values, indicating that habitat types in the Nonsan stream have relatively stable community structure. Bray-curtis cluster analysis indicated that the meander type pool and riffle showed the most similar values(80.8%). Moreover, cluster and principal component analysis were classified as 2 groups(lotic and lentic habitats).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1B
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• pp.11-20
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• 2008

The spillway type of small and midsize dams in Korea is almost overflow weir. To examine flood control capacity of overflow spillway, FLOW-3D was applied to Daesuho dam and analysis was focused on the discharge of dam spillway by changing weir shape. Overflow phases and discharges of linear labyrinth weir and curved labyrinth weir were compared with those of existing linear ogee weir. Hydraulic model experiment was performed to verify numerical result. Verification results showed that overflow behaviors and flow characteristics in the side channel by hydraulic model experiment and numerical simulation are well matched, and water surface elevation at side wall coincides with each other. When the reservoir elevation was increased up to design flood level, in case of the linear ogee weir the flow over the crest ran through smoothly in the side channel, whereas in cases of linear labyrinth weir and curved labyrinth weirs, the flow discharge was increased by 40 cms, and the flow over the weir crest, rotating counter-clockwise, was submerged in the side channel. The results of the water level-discharge curve revealed that labyrinth weir can increase discharge by 71% compared to the discharge of linear ogee weir at low reservoir elevation since it can have longer effective length. But as water surface elevation rises, the slope of water level-discharge curve of labyrinth weir becomes milder by submergence and nappe interference in the side channel.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.6
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• pp.333-339
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• 2003

It has been demonstrated that an unidentified cytosolic factor(s) reduces $K_{ACh}$ channel function. Therefore, this study attempted to elucidate the cytosolic factor. Fresh cytosol isolated from normal heart (FC) depressed the $K_{ACh}$ channel activity, but cytosol isolated from the ischemic hearts (IC) did not modulate the channel function. Electrophorectic analysis revealed that a protein of ${\sim}80 kDa was markedly reduced or even lost in IC. By using peptide sequencing analysis and Western blot, this 80 kDa protein was identified as transferrin (receptor-mediated $Fe^{3+}$ transporter, 76 kDa). Direct application of transferrin (100 nM) to the cytoplasmic side of inside-out patches decreased the open probability ($P_o$, 12.7${\pm}6.4%, n=4) without change in mean open time (${\tau}_o$, $98.5{\pm}1.3$%, n=4). However, the equimolar apotransferrin, which is free of $Fe^{3+}$, had no effect on the channel activity (N*$P_o$, $129.1{\pm}13.5$%, n=3). Directly applied $Fe^{3+}$ (100 nM) showed results similar to those of transferrin (N*$P_o$: $21.1{\pm}3.9$%, n=5). However $Fe^{2+}$ failed to reduce the channel function (N*$P_o$, $106.3{\pm}26.8$%, n=5). Interestingly, trivalent cation La3+ inhibited N*$P_o$ of the channel ($6.1{\pm}3.0$%, n=3). Taken together, these results suggest that $Fe^{3+}$ bound to transferrin can modulate the $K_{ACh}$ channel function by its electrical property as a polyvalent cation.

• Journal of Broadcast Engineering
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• v.13 no.1
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• pp.62-68
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• 2008

Remote user authentication scheme is a cryptographic tool which permits a server to identify a remote user. In 2007, Wang et al. pointed out that Ku's remote user authentication scheme is vulnerable to a dictionary attack by obtaining some secret information in a smart card using side channel attacks. They also proposed a remote user authentication scheme which is secure against dictionary attack. In this paper, we analyze the protocol proposed by Wang et al. In the paper, it is claimed that the protocol is secure even though some values, which is stored in a smart card, are revealed to an adversary, However, we show that their protocol is insecure if the values are disclosed to an adversary.

• ETRI Journal
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• v.38 no.2
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• pp.387-396
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• 2016

This paper introduces a new type of collision attack on first-order masked Advanced Encryption Standards. This attack is a known-plaintext attack, while the existing collision attacks are chosen-plaintext attacks. In addition, our method requires significantly fewer power measurements than any second-order differential power analysis or existing collision attacks.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.661-665
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• 2002

A lot of investigations have been made in recent years on the equal channel angular pressing (ECAP) which produces ultra-fine grains. The finite element method has been used to investigate this issue. In this paper, pure-Zirconium is considered far ECAP process by three dimensional finite element analysis. The effects of fiction on the deformation behavior have been investigated and compared with two dimensional finite element analysis.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.14 no.2
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• pp.108-117
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• 1985

In this study, a numerical analysis was performed for the natural convection heat transfer in a vertical channel which was consisted of two finite-thickness vertical walls with heat source. The ratio of the thermal conductivity of wall to air played an important role in the analysis. The case for which one side wall has protrusion resistances was also examined. The governing equations for the system was discretized by control volume formulation and solved by SIMPLE method. As the result of this study, it was found that the uniform heat flux boundary condition could be applied when the conductivity ratio was below approximately 50 and the uniform temperature boundary condition could be used when the conductivity rat io was over approximately 15,000. However, when the conductivity ratio was between 50 and 15,000, the thermal conductivity ratio value should be considered for the analysis. It was also found that the existence of protrusion resistance influenced the thermal field up to the distance of 3-4 times of the protrusion length.