• Journal of Educational Research in Mathematics
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• v.19 no.2
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• pp.185-206
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• 2009

In the study, I conducted the teaching experiment designed to instruct proof to four 7th grade students by utilizing the analysis method. As the results of this study I could identified that it is effective to teach and learn to find proof methods using the analysis. The results of the study showed that four 7th grade students succeeded in finding the proof methods by utilizing the analysis and representing the proof after 15 hours of the teaching experiment. In addition to the difficulties that students faced in learning proof utilizing the analysis were related to the search for the light conditions for triangles to be congruent, symbolic representation of the proof methods, reinterpretation of drawings given in the proof problems.

• Proceedings of the Korea Association of Information Systems Conference
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• 1997.10a
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• pp.105-112
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• 1997

전자상거래(Electronic Commerce)를 광범위하게 활용하기 위해서는 시큐리티 확 보 방안이 먼저 마련되어야 한다. 전자상거래와 관련된 시큐리티 문제에는 통상적인 정보보 안 이외에 메시지 발신자의 신원을 증명하는 신원 인증과, 메시지 내용의 완전성 및 정확성 을 보장하는 메시지의 완전성 보장, 그리고 메시지의 송·수신을 증명하는 부인방지 등이 있 다. 본 논문에서는 전자상거래의 시큐리티 문제를 해결하는데 필요한 메시지 인증과 디지털 서명에 대해 소개하고, 또한 메시지 인증과 디지털 서명의 핵심적인 요소인 해쉬함수를 분 석한다.

• Journal of the Korean Institute of Intelligent Systems
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• v.5 no.3
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• pp.111-116
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• 1995

본 논문의 목적은 Cao의 퍼지 추론에 기초한 퍼지 시스템이 Universal Approximator임을 증명함으로써 Cao의 퍼지 시스템을 비선형 모델링 문제에 적용하기 위한 이론적 토대를 제공하는 것이다. 즉 우리는 Cao의 퍼지 논리 시스템을 특별한 형태로 수식화하고 수식화된 Cao의 퍼지는 논리 시스템이 임의의 비선형 함수를 충분히 정확하게 근사할 수 있다는 것을 보인다. 이와 같이 증명된 이론은 Cao의 퍼지 시스템이 실제의 공학적 문제에 어떻게 성공적으로 적용되었는지를 설명할 수 있다.

• The Journal of the Acoustical Society of Korea
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• v.22 no.5
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• pp.360-366
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• 2003

Although multilayer perceptrons (MLPs) present several advantages against other pattern recognition methods, MLP-based speaker verification systems suffer from slow enrollment speed caused by many background speakers to achieve a low verification error. To solve this problem, the quantitative discriminative cohort speakers (QnDCS) method, by introducing the cohort speakers method into the systems, reduced the number of background speakers required to enroll speakers. Although the QnDCS achieved the goal to some extent, the improvement rate for the enrolling speed was still unsatisfactory. To improve the enrolling speed, this paper proposes the qualitative DCS (QlDCS) by introducing a qualitative criterion to select less background speakers. An experiment for both methods is conducted to use the speaker verification system based on MLPs and continuants, and speech database. The results of the experiment show that the proposed QlDCS method enrolls speakers in two times shorter time than the QnDCS does over the online error backpropagation(EBP) method.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.3
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• pp.169-175
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• 2002

This paper is about the hardness of the Election problem in asynchronous distributed systems in which processes can crash but links are reliable. The hardness of the problem is defined with respect to the difficulty to solve it despite failures. It is shown that problems encountered in the system are classified as three classes of problems: F (fault-tolerant), NF (Not fault-tolerant) and NFC(NF-completeness). Among those, the class NFC is the hardest problems to solve. In this paper, we prove that the Election problem is the most difficult problem which belongs to the class NFC.

• Journal of Educational Research in Mathematics
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• v.23 no.4
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• pp.585-604
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• 2013

This study is based on the problem that most middle school students cannot recognize the generality of geometrical theorems even after having proved them. By considering this problem from the point of view of empirical verification, the particularity of geometrical representations, and the role of geometrical variables, we suggest that some experiences in dynamic geometry environment (DGE) can help students to recognize the generality of geometrical theorems. That is, this study aims to observe students' cognitive changes related to their recognition of the generality and to provide some educational implications by making students experience some geometrical explorations in DGE. To do so, we selected three middle school students who couldn't recognize the generality of geometrical theorems although they completed their own proofs for the theorems. We provided them exploratory activities in DGE, and observed and analyzed their cognitive changes. Based on this analysis, we discussed the effects of DGE on studensts' recognition of the generality of geometrical theorems.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.3
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• pp.27-33
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• 2007

Recently, a new hard problem on a two dimensional vector space called vector decomposition problem (VDP) was proposed by M. Yoshida et al. and proved that it is at least as hard as the computational Diffe-Hellman problem (CDHP) on a one dimensional subspace under certain conditions. However, in this paper we present the VDP relative to a specific basis can be solved in polynomial time although the conditions proposed by M. Yoshida on the vector space are satisfied. We also suggest strong instances based on a certain type basis which make the VDP difficult for any random vector relative to the basis. Therefore, we need to choose the basis carefully so that the VDP can serve as the underlying intractable problem in the cryptographic protocols.

• Journal of Digital Convergence
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• v.18 no.3
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• pp.363-376
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• 2020

Recent studies have investigated anger or anger-related problems in adolescents from various perspectives. However, understanding of anger expression types or the role of mediating variables in relation to anger and anger expressions have been disregarded. The purpose of this research was to understand the relationships between adolescents' anger, problem solving ability, and three types of anger expressions (anger-in, anger-out, anger-control) and to focus on the mediator function of problem-solving ability. Participants comprised 596 adolescents (283 males and 313 females). Anger was significantly related to all three types of anger expressions. Adolescents who showed high anger levels tended to indicate high anger-in and anger-out expressions but low anger-control expression, while controlling for age and gender. The findings also provided evidence for the mediator role of problem-solving ability on the relationship between anger and anger-control expression. From the results of this study suggestions and limitations were also discussed.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.3
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• pp.13-22
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• 2001

The notion of pseudorandomness plays an important role in modem cryptography as well as computer science. We show a simple and practical construction of a pseudorandom generator based on the intractability of the problem in braid groups. The generator is proved as secure as a hard instance of a variant of the conjugacy problem.

• 한국어정보학회:학술대회논문집
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• 2016.10a
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• pp.79-84
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• 2016

본 연구는 전문기관에서 생산되는 검증된 문서를 웹상의 수많은 검증되지 않은 문서에 자동 주석하여 신뢰도 향상 및 심화 정보를 자동으로 추가하는 시스템을 설계하는 것을 목표로 한다. 이를 위해 활용 가능한 시스템인 인공 신경 정리 증명계(neural theorem prover)가 대규모 말뭉치에 적용되지 않는다는 근본적인 문제를 해결하기 위해 내부 순환 모듈을 단어 임베딩 모듈로 교체하여 재구축 하였다. 학습 시간의 획기적인 감소를 입증하기 위해 국가암정보센터의 암 예방 및 실천에 대한 검증된 문서들에서 추출한 28,844개 명제를 위키피디아 암 관련 문서에서 추출한 7,844개 명제에 주석하는 사례를 통하여 기존의 시스템과 재구축한 시스템을 병렬 비교하였다. 동일한 환경에서 기존 시스템의 학습 시간이 553.8일로 추정된 것에 비해 재구축한 시스템은 93.1분 내로 학습이 완료되었다. 본 연구의 장점은 인공 신경 정리 증명계가 모듈화 가능한 비선형 시스템이기에 다른 선형 논리 및 자연언어 처리 모듈들과 병렬적으로 결합될 수 있음에도 현실 사례에 이를 적용 불가능하게 했던 학습 시간에 대한 문제를 해소했다는 점이다.