• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.5
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• pp.135-140
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• 2004

In Crypto 2002 May analyzed the relation between the size of two primes and private key in unbalanced RSA with small CRT exponent. Also in Crypto 2003 he showed that if $N^{1}$4/ amount of most significant bits(least significant bits) of $d_{p}$ is exposed in balanced RSA with CRT, N can be factored. To prove this he used Howgrave-Graham's Theorem. In this paper we show that if $N^{1}$4/ amount of $d_{p}$ , p is smaller than q, and bigger than $N^{0.382}$ to avoid May's attack, is exposed in unbalanced RSA with small CRT exponent, it is enough to expose $d_{p}$ . We use Coppersmith's theorem with unbalanced primes.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.33 no.10
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• pp.50-58
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• 2004

환경에 대한 영향이 거의 없는 청정한 친환경 에너지원인 소수력 자원의 기술 개발 및 보급 추진 형황 등에 대하여 정리하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10a
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• pp.133-136
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• 2000

이 논문에서는 먼저 소수성 시험 알고리즘의 기본 개념이 되는 Fermat 의 정리를 살펴본다. 그리고, 가장 널리 사용되고 구현이 용이한 소수성 시험 알고리즘인 Rabin-Miller 및 Rivest 알고리즘을 살펴보고, 이들 알고리즘의 수행 시간을 분석한다. 또한, Rivest 가 제시한 연구 결과를 바탕으로 소수성시험 방법의 수행성능 향상 방안을 고려함으로써, Rivest 알고리즘을 효율적으로 구현하여 암호 시스템 등의 응용에 적용할 수 있도록 개선 방안을 제시한다.

• School Mathematics
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• v.12 no.3
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• pp.371-388
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• 2010

The goals of this study are to inquire middle school students' understanding about prime number and to propose pedagogical implications for school mathematics. Written questionnaire were given to 198 Korean seventh graders who had just finished learning about prime number and prime factorization and then 20 students participated in individual interviews for member checks. In defining prime and composite numbers, the students focused on distinguishing one from another by numbering of factors of agiven natural number. However, they hardly recognize the mathematical connection between prime and composite numbers related on the multiplicative structure of natural number. This study suggests that it is needed to emphasize the conceptual relationship between divisibility and prime decomposition and the prime numbers as the multiplicative building blocks of natural numbers based on the Fundamental Theorem of Arithmetic.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1188-1189
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• 2008

에너지 자원의 절대부족으로 국내 수요의 97%를 해외에서 수입해야 하는 우리나라는 화석에너지의 고갈과 환경오염 및 지구 온난화에 대처하고 에너지 자립도를 향상시키기 위하여 국내 부존에너지인 소수력 개발이 필요하다. 소수력은 다른 신.재생에너지원에 비해 천혜의 자연조건과 기술력이 확보되어 있고 국부유출이 적어서 경제성이 높은 것으로 평가되고 있다. 이처럼 소수력발전은 신.재생에너지 분야에서 비교적 우위에 있는 에너지임에도 불구하고 개발이 저조하다. 그래서 소수력발전의 기술개발 현황과 시장동향을 정리하여 국내의 소수력 발전 개발을 위한 기초자료로 사용하고자 한다.

• Communications of Mathematical Education
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• v.33 no.3
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• pp.255-273
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• 2019

In order to help students to understand the essence of prime concepts, this study looked at the history of prime concept development and analyzed how to introduce the concept of textbooks. In ancient Greece, primes were multiplicative atoms. At that time, the unit was not a number, but the development of decimal representations led to the integration of the unit into the number, which raised the issue of primality of 1. Based on the uniqueness of factorization into prime factor, 1 was excluded from the prime, and after that, the concept of prime of the atomic context and the irreducible concept of the divisor context are established. The history of the development of prime concepts clearly reveals that the fact that prime is the multiplicative atom is the essence of the concept. As a result of analyzing the textbooks, the textbook has problems of not introducing the concept essence by introducing the concept of prime into a shaped perspectives or using game, and the problem that the transition to analytic concept definition is radical after the introduction of the concept. Based on the results of the analysis, we have provided several pedagogical implications for helping to focus on a conceptual aspect of prime number.

• The Korean Journal of Archival Studies
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• no.31
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• pp.3-42
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• 2012

This paper considers some possibilities of community archives by exploring the concepts ans meanings of archival description. The author deals with two interesting cases -Herstory Writers Workshop Collection of Stony Brook University in New York and Poolmoo Collection of Poomoo Agricultural School in Korea. The author argues that archivists should know the specifications of Community Archives related to National Archives when they organizing and preserving records and archives of community archives.

• Journal of Elementary Mathematics Education in Korea
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• v.14 no.2
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• pp.377-399
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• 2010

Mixed calculations involving fractions and decimals covered in the unit 6-Na in elementary school math class cause students difficulties, leading them make lots of errors. If students fail to understand temporarily or partly what the teacher taught or lose confidence and continue to have difficulty due to a lack of understanding and skills of algorithm, though they properly understand the concept and principle of the learning content, it should be resolved through intensive teaching. For students suffering from this problem, a correct diagnosis and appropriate treatment are required. Therefore, this study developed a feedback program after diagnosing students' errors through evaluating them in order to continuously assist them to fully understand contents regarding mixed calculations involving fractions and decimals.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.46 no.1
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• pp.57-65
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• 2020

To prevent loss of hair protein during hair washing process by water through, a shield coating the pathway of water molecules was studied. Hydrophobic virgin hair, hydrophilic hair, which was damaged only methyleicosanoic acid (18-MEA) on the surface, and a repaired hair re-bound 18-MEA, were prepared and water mass changes by as heat were measured. Results showed that hydrophobic hairs followed bi-exponential function of 39 s and 151 s and other two hairs exhibited fast- and mono-exponential decay with 83 s, reflecting the extraction of water molecules without any resistance at the hydrophobic surface. On the assumption that hydrophobic surface resists an extraction of protein in water during the wash, the protein concentrations were compared from the hair of hydrophobic and hydrophilic surface. The extracted hair proteins were 179 and 148 ㎍/mL from the hair coated with hydrophilic polyethylene glycol (PEG) and hydrophobic polydimethylsiloxane (PDMS), respectively. This study suggested that hydrophobic coating on the hair surface could be used to prevent protein loss in wash, represented by LFM. In conclusion, this research provides some useful information to contribute to the development of hair washing products that can prevent protein loss in the cleaning process by granting hydrophobic coatings.

• Journal of the KSME
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• v.30 no.2
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• pp.115-130
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• 1990

기구나 구조물에 작용하는 실제하중은 진폭 등이 불규칙하게 변화하는 이른 바 변동하중으로, 강 도설계에 있어서는 이러한 변동하중하의 피로에 관하여 충분히 고려할 필요가 있다. 따라서 국 외에서는 현재까지 랜덤하중을 포함한 각종 변동하중 하에서 많은 연구가 이루어져 유익한 결 과도 얻어지고 있으나, 국내에서는 매우 단순한 변동하중하의 소수의 연구를 제외하고는, 실험 상의 어려움 등으로 주목할 만한 체계적인 연구결과가 없는 것이 실정이다. 변동하중하의 피로 문제는 근래 국내의 현장에서도 그 중요성이 점차 인식되고 있어, 국내 학술지에도 이에 관한 해설 등(1)이 약간 보이기 시작했다. 이러한 점들을 감안하여 본 글에서는 랜덤하중을 포함한 변동하중하의 피로파괴에 관하여 기초사항과 함께 기본특성을 소개해 보기로 하였으며, 아울러 관련용어들도 정리해 두기로 하였다.