• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1991.11a
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• pp.105-133
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• 1991

본 논문에서는 임의의 이진 난수발생기의 source가 $BMS_{p}$ 이거나 M-memory를 갖는 마르코프연쇄로 모델화 되었을 경우에 비트당 entropy와 관련이 있는 새로운 randomness에 관한 통계적 검정법을 제안한다. 기존에 알려진 이진 난수발생기의 randomness검정법이 0또는 1의 분포의 편향성(bias)이나 연속된 비트간의 상관성(correlation)중의 한 종류만의 non-randomness를 추적해낼 수 있는 반면에 새로운 검정법은 위의 두가지 검정을 통과하였을 때 암호학적으로 중요한 측도인 비트당 entropy 를 측정하여 암호학적인 약점을 검정할 수 있다. 또한 대칭(비밀키) 암호시스템의 통계적 결점을 바탕으로 하여 키를 찾는 공격자의 최적 전략( optimal strategy)문제를 분석하여 이 최적 전략이 이진 수열의 비트당 entropy와 밀접한 관계가 있음을 보이고 이 비트당 entropy와 관련이 있는 새로운 통계량을 도입하여 이진 난수 발생기의 source의 이진수열이 다음 3가지 경우, 즉, i.i.d. symmetric인 경우, $BMS_{p}$ 인 경우, M-memory를 갖는 마르코프연쇄인 경우의 각각에 대하여 특성을 조사하고 새로운 통계량의 평균과 분산을 구한다. 이때 구한 새로운 통계량은 잘 알려진 중심 극한 정리에 의하여 근사적으로 정규분포를 따르므로 위의 평균과 분산을 이용하여 스트림 암호시스템에서 구성요소로 많이 사용되는 몇 몇 간단한 이진 난수 발생기에 적용하여 통계적 검정을 실시함으로써 entropy 관점의 검정법이 새로운 randomness 검정법으로 타당함을 보인다.

• The Korean Journal of Applied Statistics
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• v.27 no.1
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• pp.115-122
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• 2014

A test for randomness of the binary random sequence is proposed in this paper. The proposed test statistic is based on the mean length of runs distributed with truncated geometric distribution and asymptotically ${\chi}^2_2$-distributed when the size of the sequences is large. A small Monte Carlo simulation compared the size of the test with a significant level as well as evaluated the test power. We applied the proposed method to the sequence of yes or no numbers in Lotto 6/45 and concluded that the randomness of Lotto is retained.

• The Journal of the Acoustical Society of Korea
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• v.12 no.2E
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• pp.27-32
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• 1993

이 논문에서는 충격성 잡음이 있는 비선택적 라이시안 페이딩 채널에서 부호 상관 수신기를 쓴 DS/SSMA 계통의 성능을 분석하였다. 이 계통의 평균 이진 오류 확률을 확산 수열이 짧을 때에는 정확한 계산으로, 확산 수열이 길 때에는 근사적인 방법으로 얻었다.

• Journal of Broadcast Engineering
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• v.4 no.2
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• pp.144-154
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• 1999

The binomial sequences are family of orthogonal sequences that can be generated with remarkable simplicity-no multiplications are necessary. This paper introduces a class of non-recursive multidimensional filters for frequency-selective image processing without multiplication operations. The magnitude responses are narrow-band. approximately gaussian-shaped with center frequencies which can be positioned to yield low-pass. band-pass. or high-pass filtering. Algorithms for the efficient implementation of these filters in software or in hardware are described. Also. we show that the binomial QMFs are the maximally flat magnitude square Perfect Reconstruction paraunitary filters with good compression capability and these are shown to be wavelet filters as well. In wavelet transform the original image is decomposed at different scales using a pyramidal algorithm architecture. The decomposition is along the vertical and horizontal direction and maintains constant the number of pixels required to describe the images. An efficient perfect reconstruction binomial QMF-Wavelet signal decomposition structure is proposed. The technique provides a set of filter solutions with very good amplitude responses and band split. The proposed binomial QMF-filter structure is efficient, simple to implement on VLSl. and suitable for multi-resolution signal decomposition and coding applications.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2000.11b
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• pp.87-92
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• 2000

본 논문에서는 컨텍스트 기반 계층적 열거 부호화를 이용한 무손실 이진 영상 압축 알고리즘을 제안한다. 이진 영상내에 존재하는 인접한 화소간의 상호상관성을 이용하여 이진 영상을 1차원의 수열로 재구성하고, 이에 대해 계층적 열거 부호화를 실행한다. 제안하는 알고리즘은 덧셈 및 비교 연산만으로 구현이 가능하므로 그 복잡도가 매우 낮을 뿐만 아니라, CCITT 테스트 영상을 대상으로 한 부호화 성능 실험에서 우수한 성능을 나타낸다. 부호화 성능 비교에서 이진 영상 부호화 국제표준인 JBIG, G3, G4 및 GIF에 비해 우수한 압축 성능을 보인다.

• The KIPS Transactions:PartB
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• v.10B no.5
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• pp.485-490
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• 2003

In this paper, we propose the possibility of introducing chaotic sequences into digital watermarking systems as potential substitutes to commonly used pseudo noise sequences. Chaotic sequences have several good properties including the availability of a great number of them, the ease of their generation, as well as their sensitive dependence on their initial conditions. And the quantization does not destroy the good property. So this paper proposes a method that transforms Hangul text to chaotic sequence. And we presents how the Hangul text is expressed by an implied data and the implied data is regenerated into the original text. In this paper, we use this implied Hangul text for watermarking.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.8
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• pp.445-452
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• 2014

In this paper, we define ideal autocorrelation property for balanced quaternary sequence with even period. We also prove that our definition is ideal autocorrelation property for balanced quaternary sequence with even period. Furthermore, we propose a generation method of quaternary sequence with ideal autocorrelation property of period $2{\times}(2^n-1)$ using a binary sequence with ideal autocorrelation of period $2^n-1$ and Gray mapping. We also derive the autocorrelation value distribution of the newly proposed quaternary sequence.

• Korea Journal of Geothermal Energy
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• v.9 no.3
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• pp.34-43
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• 2013

• The KIPS Transactions:PartC
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• v.8C no.1
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• pp.12-15
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• 2001

A summation generator creates sequence from addition with carry of LFSR (Linear Feedback Shift Register) sequences. Similarly, it is possible to generate keystream by bitwise exclusive-oring on two FCSR sequences. In this paper, we described the cryptographic properties of a sequence generated by the FCSRs.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.3
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• pp.77-85
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• 2002

A Research of binary random sequence generator that uses a linear shift register had been studied since the 1970s. These generators were used in stream cipher. In general, the binary random sequence generator consists of linear shift registers that generate sequences of maximum period and a nonlinear filter function or a nonlinear combination function to generate a sequence of high linear complexity. Therefore, To generate a sequence that have long period as well as high linear complexity becomes an important factor to estimate safety of stream cipher. Usually, the maximum period of the sequence generated by a linear feedback shift register with L resistors is less than or equal to $2^L$-1. In this paper, we propose new binary random sequence generator that consist of L registers and 2 sub-characteristic polynomials. According to an initial state vector, the least period of the sequence generated by the proposed generator is equal to or ions than it of the sequence created by the general linear feedback shift register, and its linear complexity is increased too.