• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.251-262
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• 2011

Human ether-a-go-go related gene (hERG) potassium channel blockade, an undesirable side effect which might cause sudden cardiac death, is one of the major concerns facing the pharmaceutical industry. The purpose of this study is to develop an in silico QSAR model which uncovers the structural parameters of T-type calcium channel blockers to reduce hERG blockade. Comparative molecular similarity indices analysis (CoMSIA) was conducted on a series of piperazine and benzimidazole derivatives bearing methyl 5-(ethyl(methyl)amino)-2-isopropyl-2-phenylpentanoate moieties, which was synthesized by our group. Three different alignment methods were applied to obtain a reliable model: ligand based alignment, pharmacophore based alignment, and receptor guided alignment. The CoMSIA model with receptor guided alignment yielded the best results : $r^2$ = 0.955, $q^2$ = 0.781, $r^2_{pred}$ = 0.758. The generated CoMSIA contour maps using electrostatic, hydrophobic, H-bond donor, and acceptor fields explain well the structural requirements for hERG nonblockers and also correlate with the lipophilic potential map of the hERG channel pore.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.7
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• pp.730-738
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• 1992

This paper alms to analyse the performance of frequency hopping /spread spectrum multiple access system by employing the channel with mixture of AWGN, partial band Jamming, fading and user interference. The performance analysis of FH /SSMA system, taking account of frequency 'hit'(user Interference ) which occurs in the presence of multiple user, produces the following numerical results by computing error probability and throughput of each code in two cases whether the side Information about channel is used or not. The numerical results are as follows : When composite interferences coexist In channel, RS code Is significantly superior to convolutional code in terms of performance. Concatenated code provides the same performance as RS code. The above results show that RS code is pertinent as error-correction code.

• Journal of Korea Water Resources Association
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• v.56 no.1
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• pp.23-34
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• 2023

This study analyzed the bed load transport and channel change on the vegetation zone through laboratory experiments and numerical simulations. To examine the effect of vegetation zone in the laboratory experiment, artificial vegetation zones made of acrylic sticks were installed in the experimental channel, and discharge conditions were adjusted to examine the bed load transport and channel change in the vegetation zone. Next, numerical simulations were performed by applying the same conditions as those of the laboratory experiment to the Nays2D model, a two-dimensional numerical model, and the applicability of the numerical model was examined by comparing the results with the results of the laboratory experiment. Finally, by applying a numerical model, the bed load transport and channel change according to the change in vegetation density were examined. As a result of examining the bed load transport and channel change in the vegetation zone according to the discharge condition change by applying the laboratory experiment and the numerical model, the results of the two application methods were similar. As the discharge increased, bed load from the upper stream was deposited inside the vegetation zone. On the other hand, on the other side of the vegetation zone, the flow was concentrated and erosion occurred. Also, the range of erosion increased in the downstream direction. As a result of examining the bed load transport and channel change according to the change in vegetation density, as the vegetation density increased, the bed load from the upper stream was deposited inside the vegetation zone. On the other hand, due to the increase in vegetation density, the flow was concentrated to the opposite side of the vegetation zone, erosion occurred.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.1
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• pp.261-269
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• 2014

There are many researches on fast exponentiation algorithm which is used to implement a public key cryptosystem such as RSA. On the other hand, the malicious attacker has tried various side-channel attacks to extract the secret key. In these attacks, an attacker uses the power consumption or electromagnetic radiation of cryptographic devices which is measured during computation of exponentiation algorithm. In this paper, we propose a novel simple power analysis attack on m-ary exponentiation implementation. The core idea of our attack on m-ary exponentiation with pre-computation process is that an attacker controls the input message to identify the power consumption patterns which are related with secret key. Furthermore, we implement the m-ary exponentiation on evaluation board and apply our simple power analysis attack to it. As a result, we verify that the secret key can be revealed in experimental environment.

• 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.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.6
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• pp.3-13
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• 2010

Differential Fault Analysis (DFA) is widely known for one of the most efficient method analyzing block cipher. In this paper, we propose a new type of DFA on DES (Data Encryption Standard). DFA on DES was first introduced by Biham and Shamir, then Rivain recently introduced DFA on DES middle rounds (9-12 round). However previous attacks on DES can only be applied to the encryption process. Meanwhile, we first propose the DFA on DES key-schedule. In this paper, we proposed a more efficient DFA on DES key schedule with random fault. The proposed DFA method retrieves the key using a more practical fault model and requires fewer faults than the previous DFA on DES.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.8
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• pp.17-24
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• 2004

Quantum effects in the poly-gate are analyzed in two dimensions using the density-gradient method, and their impact on the short-channel effect of double-gate MOSFETs is investigated. The 2-D effects of quantum mechanical depletion at the gate to sidewall oxide is identified as the cause of large charge-dipole formation at the corner of the gate. The bias dependence of the charge dipole shows that the magnitude of the dipole peak-value increases in the subthreshold region and there is a large difference in carrier and potential distribution compared to the classical solution. Using evanescent-nude analysis, it is found that the quantum effect in the poly-gate substantially increases the short-channel effect and it is more significant than the quantum effect in the Si film. The penetration of potential contours into the poly-gate due to the dipole formation at the drain side of the gate corner is identified as the reason for the substantial increase in short-channel effects.

• Journal of IKEEE
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• v.27 no.4
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• pp.399-404
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• 2023

In this paper, we analyzed the current path in the O/N/O (Oxide/Nitride/Oxide) structure of 3D NAND Flash memory and in the O/N/F (Oxide/Nitride/Ferroelectric) structure where the blocking oxide is replaced by a ferroelectric. In the O/N/O structure, when V_read is applied, a current path is formed on the backside of the channel due to the E-fields of neighboring cells. In contrast, the O/N/F structure exhibits a current path formed on the front side due to the polarization of the ferroelectric material, causing electrons to move toward the channel front. Additionally, we performed an examination of device characteristics considering channel thickness and channel length. The analysis results showed that the front electron current density in the O/N/F structure increased by 2.8 times compared to the O/N/O structure, and the front electron current density ratio of the O/N/F structure was 17.7% higher. Therefore, the front current path is formed more effectively in the O/N/F structure than in the O/N/O structure.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2003.07a
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• pp.83-88
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• 2003

부채널 공격(side channel attack)을 막는 새로운 접근방법으로 생각되는 랜덤 부호화 스칼라 곱 알고리즘은 Ha와 Moon에 의해서 제안되었다. 그러나 이 방법은 여전히 논쟁의 여지가 있다. 본 논문에서는 Ha-Moon 알고리즘이 기존의 세 가지 단순 전력 소모량 분석(simple power analysis, SPA)에 안전함을 보인다. 그리고 정수론의 성질을 이용하여 두 가지 중요한 정리를 제시하고 이 정리들을 이용하여 Ha-Moon 알고리즘에 적용할 수 있는 공격 알고리즘을 개발한다. 예를 들면, 163-비트 키들에 대하여 제안 알고리즘은 20개의 전력 소모량을 이용하여 키 복잡도 Ο(2$^{8}$ )를 가지고 공격할 수 있다.

• Electronics and Telecommunications Trends
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• v.28 no.3
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• pp.47-56
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• 2013

부채널 분석은 암호 알고리즘이 장치 내에서 동작하는 동안에 장치의 전력이나 전자파 등의 부가 정보의 수집, 가공 및 통계적인 분석을 통해 키 정보를 추출해내는 매우 강력한 공격 방법이다. 부채널 분석 시스템은 암호 모듈이 탑재되는 장치가 부채널 공격에 대해 안전한지를 사전 검증 및 시험할 수 있는 방법들을 제공한다. 본고에서는 다양한 부채널 분석 방법 및 이를 제공하는 부채널 분석 시스템에 대한 현황 및 전망을 기술한다.