• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.5
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• pp.87-93
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• 2002

SHACAL is based on the hash standard SHA-1 used in encryption mode, as a submission to NESSIE. SHACAL uses the XOR, modular addition operation and the functions of bit-by-bit manner. These operations and functions make the differential cryptanalysis difficult, i.e, we hardly find a long differential with high probability. But, we can find short differentials with high probability. Using this fact, we discuss the security of SHACAL against the amplified boomerang attack. We find a 36-step boomerang-distinguisher and present attacks on reduced-round SHACAL with various key sizes. We can attack 39-step with 256-bit key, and 47-step with 512-bit key.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.1
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• pp.49-57
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• 2003

The flight trajectory of a boomerang is predicted with the momentum theory (actuating disk theory) and the blade element method generally used as tools to analyze in the rotary-wing aerodynamics. Boomerangs made by students are actually compared with the computational results, utilized to get the physical intuition. The transition from helicopter mode to autogyro mode with the gyroscopic precession is observed in numerical analysis and experiment like a 'flying rotor' after the boomerang taking off. The whole system is shown to be highly nonlinear and very sensitive to the initial conditions. Various flight loci may be obtained if we change the parameters.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.373-373
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• 2016

파푸아뉴기니 열대 우림에 서식하는 극락조의 가슴깃은 독특한 나노 구조를 가지고 있다. 이 독특한 구조에 의해 구조색이 발현된다. 또한 이 구조색은 입사하는 빛의 각도에 따라 색이 변화 하며 아름다운 색을 낸다. 극락조의 가슴깃의 구조는 keratin과 melanin으로 구성 되어 있는데 keratin과 melanin이 한 층씩 교대로 위치하여 multi layer 구조를 가진다. 가슴깃의 단면의 형태는 부메랑 모양의 구조로 되어 있는데 물질은 주로 keratin 으로 이루어져 있고 keratin 내부에 melanin rodlet이 층층이 박혀서 multi layer를 형성한다. 부메랑 모양의 단면에서 keratin 피질의 각도는 약 $30^{\circ}$ 정도로 이루어져 있고 내부의 melanin 기둥이 이루는 층은 약 $11.3^{\circ}$ 정도로 이루어져 있다. 본 연구에서는 극락조 가슴깃의 구조를 도식화 하여 입사하는 빛의 각도에 따라 나타나는 구조색을 FDTD simulation을 통해 계산하였고 실제 구조에 의해 측정된 reflectance spectra와 비교하여 특성이 유사하게 나타남을 확인 하였다. 실제 극락조 가슴깃의 반사 특성은 부메랑 모양 구조의 가운데 부분에서는 파장이 610 nm 정도인 주황빛이 주로 반사가 되고, 부메랑 모양 구조의 양옆 부분에서는 파장이 420 nm 정도인 파란빛이 주로 반사되어 나타난다. 그리고 각도에 따른 구조색의 변화는 보통의 multi layer의 특징과 다르게 나타난다. 입사하는 빛의 각도가 커질수록 reflectance peak가 나타나는 파장이 점점 짧아지는 특징은 일반적인 multi layer와 일치하지만 일반적인 multi layer가 입사 각도가 커질수록 reflectance가 커지는데 반해 극락조 가슴깃의 반사특성은 입사 각도가 커질수록 reflectance는 오히려 작아진다. 우리가 도식화한 구조를 FDTD simulation한 결과는 이러한 특징이 실제 구조의 측정 결과와 일치하게 잘 나타났다. 또한 keratin과 melanin층의 각도 및 두께변화에 따른 reflectance를 FDTD simulation을 통해 계산 해보았고 구조변화에 따른 특징들을 확인해 보았다.

• 베이커리
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• no.4 s.393
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• pp.106-109
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• 2001

• Korea Petroleum Association Journal
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• no.3 s.61
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• pp.52-53
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• 1986

• Korean Architects
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• s.598
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• pp.26-33
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• 2019

• Korean Architects
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• s.598
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• pp.34-35
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• 2019

• The KIPS Transactions:PartC
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• v.19C no.1
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• pp.55-62
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• 2012

KT-64 is a 64-bit block cipher which use CSPNs suitable for the efficient FPGA implementation. In this paper, we propose a related-key amplified boomerang attack on the full-round KT-64. The attack on the full-round KT-64 requires $2^{45.5}$ related-key chosen plaintexts and $2^{65.17}$ KT-64 encryptions. This work is the first known cryptanalytic result on KT-64.

• Journal of Digital Convergence
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• v.16 no.2
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• pp.351-359
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• 2018

The purpose of this research is to arouse attention to the importance of eliminating the 'Shadow Encroaching Phenomena on the Essence' in advertising expression by interdisciplinarily applying ethicality. This research shows that when advertising expression is planned and executed without enough consideration of ethicality, short-term effectiveness to reach goals can be increased, but it is easy to induce an unintended 'Shadows' Boomerang Phenomena'. This research also proposes that such processes arouse consumers' ethical defense mechanisms, possibly causing the 'Shadow Encroaching Phenomena' in the end. In conclusion, this research proposes the following. First, the pursuit of commercial profit in a capitalistic society must be done under the premise of securing a consensus of ethicality in a common society. Second, under the premise of an integrated process of education, sharing, execution, and confirmation of ethicality, companies can achieve both the micro-practical goal of profit pursuit and the macro-environmental goal of ecological sympathy.

• Korea and Global Affairs
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• v.3 no.2
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• pp.5-58
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• 2019

The purpose of this article is to bring about 10.26 accident by providing a fuse for the overthrow of the Park Chung-hee administration in the 10.18 Buma uprising. So, first of all, this article has a main purpose in analyzing the comparison between Masan's 3.15 uprising and 10.18 Buma uprising. The purpose of the study is to compare the 3.15 democratic movement in Masan with the 10.18 Buma uprising, given that the incident laid the foundation for the dictator to be overthrown in the event of an anti-dictatorial movement in Masan. The research method of this article is intended to be used as a research method in the 3.15 and 10.18 protests, given that if a person in power conducts election fraud or suppresses anti-government movements in order to maintain the system, it could lead to the destruction of those in power. In the end, the Masan 3.15 uprising and 10.18 uprising failed to reach a direct attempt to overthrow the regime due to unfinished democratic movements, but with the revolution of 4.19 and the massive political transformation of 10.26 Accident, he achieved the leading role theory that allowed the Rhee Syngman and Park Chung-hee administrations. In eradicating authoritarian regimes, however, the historic significance of the democratization movement was that the authoritarian regime eventually brought about the collapse of the regime by making a hard-line stance on election schemes or popular protests over the trap of power boomerang, which causes the regime to collapse.