• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.12
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• pp.573-579
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• 2005

Dynamic analysis of a transmission line which is compensated by a FACTS device such as STATCOM, SSSC and UPFC is carried out in this paper and the impacts on conventional line protection methods such as the DCPM (Differential Current Protection Method) and the DPM (Distance Protection Method) are reviewed. A refined DCRM is proposed to detect faults properly regardless of the FACTS operation. The proposed method is applied to a FACTS-compensated line with a variety of faults and is verified by simulation results. An adaptive DPM on a FACTS-compensated line was proposed previously in the literature. In order to emphasize the necessity of the modified DPM, the conventional DPM is applied to a FACTS-compensated system. Significant factors such as fault types, fault locations, and fault resistances as well as FACTS device types are considered for relaying setting.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.11
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• pp.1542-1548
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• 2018

When any faults occurred in electrical railway system, operators need to analysis it quickly and accurately. Existing COMTRADE based analysis tools are not enough to analysis faults occurred in electrical railway system. In this paper, it presents some functions to fault analysis for electrical railway system based on fault data formatted COMTRADE. These functions are implemented in PSCAD/EMTDC and it can be shown that analyzed results against actual electrical fault cases which were occurred in the electrical railway power system.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.5
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• pp.1009-1017
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• 2012

The fault injection attack has been developed to extract the secret key which is embedded in a crypto module by injecting errors during the encryption process. Especially, an attacker can find master key of AES using injection of just one byte. In this paper, we proposed a countermeasure resistant to the these fault attacks by checking the differences between input and output. Using computer simulation, we also verified that the proposed AES implementation resistant to fault attack shows better fault detection ratio than previous other methods and has small computational overheads.

• 한국초전도학회:학술대회논문집
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• v.11
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• pp.71-71
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• 2001

• Proceedings of the KIEE Conference
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• 2006.10b
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• pp.136-140
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• 2006

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.5
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• pp.15-25
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• 2011

A differential fault analysis(DFA) is one of the most important side channel attacks on block ciphers. Most block ciphers, such as DES, AES, ARIA, SEED and so on., have been analysed by this attack. In 2008, Wei et al. proposed the first DFA on ARIA-128. Their attack can recover the 128-bit secrey key by about 45 faulty ciphertexts. In this paper, we propose an improved DFA on ARIA-128. We can recover the 12S-bit secret key by only 4 faulty ciphertexts with the computational complexity of O($2^{32}$).

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.52 no.4
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• pp.179-188
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• 2003

Percentage differential characteristic scheme has been recognized as the principal basis for large transformer protection. Nowadays, relaying signals can contain second harmonic component to a large extent even in a normal state, and second harmonic ratio indicates a tendency of relative reduction because of the advancement of transformer's core material. And then, conventional second harmonic restraint differential relaying exposes some doubt in reliability. It is, therefore, necessary to develop a new algorithm for the effective and accurate discrimination. This paper deals with advanced fuzzy logic based relaying by using flux differential, and a new fault detection criterion logic scheme by using wavelet transform. To comparative analysis of proposed techniques, the paper constructs power system model including power transformer, utilizing the EMTP, and collects data through simulation of various internal faults and magnetizing inrush. The proposed fuzzy relaying and a new fault detection scheme were tested. The former, fuzzy relaying, was proven to be faster and more reliable than the latter.

• Proceedings of the KIEE Conference
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• 2004.07e
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• pp.92-95
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• 2004

Power transformer is an important apparatus in transforming and delivering the power in a power system. It shows less accident ratio than other system apparatus, but once the accident occurs, it causes long-term operation stoppage and economic loss. It brings high bad spillover effects. Therefore, the role of protective relaying, which is to prevent internal fault a power transformer is highly important. This study proposed advanced algorithm that can clearly determine internal fault of the power transformer and magnetizing inrush, through numerical analysis by using the terminal voltage and input output current.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.1
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• pp.33-41
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• 2012

A differential fault analysis(DFA) is one of the most important side channel attacks on block ciphers. Most block ciphers, such as DES, AES, ARIA, SEED and so on., have been analysed by this attack. PRESENT is a 64-bit block cipher with 80/128-bit secret keys and has a 31-round SP-network. So far, several DFAs on PRESENT have been proposed. These attacks recovered 80, 128-bit secret keys of PRESENT with 8~64 fault injections. respectively. In this paper, we propose an improved DFA on PRESENT-80/128. Our attack can reduce the complexity of exhaustive search of PRESENT-80(resp. 128) to on average 1.7(resp. $2^{22.3}$) with 2(resp. 3) fault injections, From these results, our attack results are superior to known DFAs on PRESENT.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.2
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• pp.91-95
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• 2008

The large AC generator fault may lead to large impacts or perturbations in power system. The generator protection control systems in Korea have been imported and operated through a turn-key from overseas entirely. Therefore a study of the generator protection field has in urgent need for a stable operation of the imported goods. In present, the algorithm using the current ratio differential relaying based DFT for stator winding protection or a fault detection had been applied that of internal fault protection of a generator. the DFT used for the analysis of transient state signal conventionally had defects losing a time information in the course of transforming a target signal to frequency domain. In this paper, the discrete wavelet transform (DWT) was applied a fault detection of the generator being superior to a transient state signal analysis and being easy to real time realization. The fault signals after executing a terminal fault modeling collect using a MATLAB package, and calculate the wavelet coefficients through the process of a muiti-level decomposition (MLD). The proposed algorithm for a fault detection using the Daubechies WT (wavelet transform) was executed with a C language and the commend line function for the real time realization after analyzing MATLAB's graphical interface. The advanced technique had improved faster a speed of fault discrimination than a conventional DFR based on DFT.