• The Journal of the Korea Contents Association
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• v.8 no.7
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• pp.53-57
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• 2008

The discretized saw-tooth map with the 16-bit finite precision which is one of the 1-dimensional chaotic maps is designed, and the circuit of chaotic binary sequence generator using the discretized saw-tooth map is presented also in this brief. The real implementation of designed chaotic map is accomplished by connecting the input and output lines exactly according to the simplified Boolean functions of output variables obtained from truth table which is discretized. The random binary output sequences generated by mLFSR generator were used for the inputs of descretized saw-tooth map, and, by the descretized map, chaotic binary sequence which has more long period of 16 times minimally is generated as a results.

• Journal of IKEEE
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• v.24 no.2
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• pp.543-549
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• 2020

As the importance of security increases in various fields, research on a random number generator (RNG) used for generating an encryption key, has been actively conducted. A high-quality RNG is essential to generate a high-performance encryption key, but the initial pseudo-random number generator (PRNG) has the possibility of predicting the encryption key from the outside even though a large amount of hardware resources are required to generate a sufficiently high-performance random number. Therefore, the demand of high-quality true random number generator (TRNG) generating random number through various noises is increasing. This paper examines and compares the representative TRNG methods based on metastable-based and ring-oscillator-based TRNGs. We compare the methods how the random sources are generated in each TRNG and evaluate its performances using NIST SP 800-22 tests.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2003.07a
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• pp.57-61
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• 2003

Iwata 등은 SPN 구조에 기반한 블록 암호들 중 Serpent에 대한 의사 난수성을 분석하였다 ［2］. 그들은 Serpent의 구조를 최대한 보존한 상태에서 의사 난수성을 분석하기 위하여 Serpent의 Diffusion layer의 특성을 그대로 보존하여 일반화 한 후 이론을 전개하였다. 본 논문에서는 Serpent가 취한 Diffusion layer 뿐만 아니라 SPN 구조에 기반한 블록 암호들이 취할 수 있는 임의의 Diffusion layer에 대하여 적용 가능한 일반적인 이론을 도출해낼 것이다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1937_1938
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• 2009

이 논문에서는 1차원 혼돈맵들 중의 하나인 톱니맵을 8비트의 유한정밀도로 이산화시켜 설계하였고, 이 이산화된 톱니맵을 사용한 혼돈 2진 순서 발생기의 회로도도 제시하였다. 설계된 혼돈맵의 실제 구현은 이산화된 진리표로부터 얻어진 출력변수의 간략화된 부울함수에 따른 입력선과 출력선들의 정확한 연결만에 의해 실현하였다. 최대길이를 발생시키는 선형궤환시프트레지스터(mLFSR)에 의해 발생되는 난수성 2진 출력 순서들을 이산화된 톱니맵의 입력순서로 사용함으로써 결과적으로 최소 8배 더 긴 주기를 갖는 혼돈 2진 순서들을 발생시켰다.

• The Journal of the Korea Contents Association
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• v.8 no.4
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• pp.86-91
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• 2008

To present the design procedure of discretized 8-bit tent map executing the transformation of tent function which is one of the chaotic functions, first, the truth table of discretized tent map was written, and then according to the simplified Boolean algebra equations obtained from the truth table, the discretized map is implemented with the exclusive logic gate as a real hardware. The discretized tent map circuit which provides the feedback circuit for generating the period-8 states relevant to the 8-bit finite precision is also designed and presented in this paper. Furthermore, it might be used stream cipher system with a new key-stream circuit for generate of chaotic binary sequence.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.433-436
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• 2009

Many researchers had made a diversity of attempts for generating pseudorandom sequences such as the method of using LFSR whose characteristic polynomial is a primitive polynomial, of using Cellular Automata and of using quadratic functions. In this paper, we can analyze and characterize the methods for generating maximal period pseudorandom sequences constructed by quadratic functions.

• Review of KIISC
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• v.5 no.2
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• pp.90-96
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• 1995

Gollmann이 제안한 Cascade 생성기는 비선형성, 발생되는 수열의 난수특성, 주기성등 암호 알고리즘으로서 필요한 제반 특성을 보장하기 때문에 그동안 스트림 암호의 핵심 논리로 널리 사용되어 왔다. 그러나 최근 생성기 내부의 각 단계별로 시각 제어 수열과 출력 수열 사이에 암호 알고리즘으로는 부적당한 상관관계 특성이 존재함이 입증되었다. 본 고에서는 이러한 상관관계 특성을 이용하여,. 단순 순환 쉬프트 래지스터로 구성된 Cascade 생성기에 대한 기지 평문 공격 방식을 제안한다. 기존의 Lock-in effect 공격방식에 대하여 $10^{21}$ 정도의 안전성을 보장하는 8단계 11-cycle Cascade 생성기에 본 방식을 적용한 결과 불과 88,000 출력 비트만을 사용하여 공격이 성공함을 실험적으로 입증하였다.

• Communications for Statistical Applications and Methods
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• v.15 no.4
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• pp.563-585
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• 2008

This paper presents how to improve the efficiency and accuracy in the pricing and sensitivity evaluation for derivatives, since the need for the evaluation of complicated derivatives is increased. The Monte Carlo(MC) simulation using the quasi random number instead of pseudo random number can improve the elapsed time and accuracy for the valuation of European-type derivatives. However, the quasi MC simulation method has its limit for applying it in the multi-dimensional case such as American-type and path-dependent options due to the increased correlation between dimensions as the dimension of random numbers is increased. In order to complement this problem, we develop a modified method in which correlation values are controlled to be below a pre-specified value. Thus, this method is applicable for the pricing of either derivatives ill which underlying assets or risk factors are several or derivatives having path-dependent or early redemption property. Furthermore, we illustrate that it is important to take an appropriate grid interval for the use of finite difference method(FDM) by applying the FDM to one example of non-symmetrical butterfly spreads.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.2
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• pp.383-390
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• 2018

Since cellular automata(CA) is superior to LFSR in randomness, it is applied as an alternative of LFSR in various fields. However, constructing CA corresponding to a given polynomial is more difficult than LFSR. Cattell et al. and Cho et al. showed that irreducible polynomials are CA-polynomials. And Cho et al. and Sabater et al. gave a synthesis method of 90/150 CA corresponding to the power of an irreducible polynomial, which is applicable as a shrinking generator. Swan characterizes the parity of the number of irreducible factors of a trinomial over the finite field GF(2). These polynomials are of practical importance when implementing finite field extensions. In this paper, we show that the trinomial $x^{2^n-1}+X+1$ ($n{\geq}2$) are CA-polynomials. Also the trinomial $x^{2^a(2^n-1)}+x^{2^a}+1$ ($n{\geq}2$, $a{\geq}0$) are CA-polynomials.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.4
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• pp.434-440
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• 1996

This experiment were conducted to elucidate the damage by viviparity during grain filling on grain quality and hulling recovery and to understand the varietal differences of viviparity and the effect of extractive from rice hull of hardly viviparous varieties on seed germination and seedling growth. Ten rice cultivars, such as three indica, four japonica and three Tongil-type rices, were used in this study. The brown rice yield was decreased along with increasing the artificial viviparous treatment periods. At six days after treatment, brown rice yield of Daeseongbyeo was reduce 20% as compared with control. The ratio of head rice was 41.3% at six days after viviparous treatment with $25^{\circ}C$ temperature and over 95% relative humidity, while it was 99.5% in control. Varietal differences of viviparity in three rice groups were ranged from 1.1 to 5.2% in indica rices, 9.2 to 79.7% in japonica rices and 2.1 to 63.7% in Tongil-type rices. Methanol extractives from rice hull of IR36, Shinunbongbyeo and Jungwonbyeo inhibited significantly the germination of Deaseongbyeo.