• Journal of Industrial Technology
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• v.18
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• pp.61-67
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• 1998

이 논문에서는 Diruchlet 경계 조건을 갖는 비선형 타원형 방정식 $-{\Delta}u+g(u)=f(x)$의 해의 존재에 대한 연구를 하였다. 존재하는 해의 다중성을 증명하기 위하여 임계점 이론과 롤의 정리를 사용하였으며, 대응되는 범함수에 따라서 방정식의 해와 임계점이 동시에 나타난다는 정리를 이용하였다. 이 때 $g(u)=bu^+-au^-$으로 나타날 때 외력항 (방정식의 우변)의 상수로 주어지는 경우 적어도 두 개의 해가 존재한다는 것을 증명하였다. 만약 우변(외력항)의 상수가 음수이거나 0인 경우이 방정식의 해가 존재하지 않거나 자명한 해만 존재하기 때문에 상수는 양수인 것으로 가정하였다.

• Annual Conference of KIPS
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• 2002.04b
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• pp.991-994
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• 2002

A. Shamir 는 비밀 정보 D를 n개의 조각으로 나눈 후, $k(k{\leq}D)$개의 조각으로는 D를 복원할 수 있으나, (k-1)개 이하의 조각으로는 복원할 수 없는 비밀 분산 방식을 처음으로 소개하였다. 이 방식은 대수학에서의 체(field) 이론에서 중요한 위치를 차지하고 있는 다항식에 대한 Lagrange interpolation에 기반하고 있으며, 키 복구 시스템 등에 실제로 사용되고 있다. 그 후에, Tompa 등은 Shamir 의 방식이 어떤 형태의 속임수에 대하여 안전하지 않음을 보이고 이 방식을 약간 변형하여 속임수에 대해 안전한 방식을 제안하였다. Tompa 등이 제안한 방식은 안전성이 어떤 증명 되지않은 가정에 의존하지 않는다는 Shamir 방식의 특성을 보존한다. 본 고에서는 위의 방법들을 수학적으로 세밀히 분석하여 보다 자세한 증명들을 제시하고, 키 복구 시스템에 적용하는 경우에 있어 각 방식의 유용성과 단점들을 비교한다.

• 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.

• Journal of Korea Game Society
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• v.9 no.6
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• pp.45-56
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• 2009

This Study has limited our scope to the study of satisfaction factor. Due to the extensiveness of fun factors of games. We had identified satisfaction factors through investigating various theories based on funology. Then, we have directly applied the satisfaction factors to games in order to define the satisfaction factors of online FPS game. Then, we have applied the satisfaction factors on to four online games, at the first phase of the study. We interviewed a group of online FPS game experts to identify the constituent elements of the factors and concluded the second phase of our investigation based on the results from the first and second phases, we have conducted a survey to verify the hypothesis. We have verified the reciprocal relationship between the satisfaction factors and game popularity by conducting a multiple regression analysis on the survey results. To conclude, there is a correlation between online FPS games and the satisfaction factors; the satisfaction factors cause the users to be absorbed into the game and to enjoy it for a long period of time.

• Korean Journal of Logic
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• v.16 no.3
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• pp.407-436
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• 2013

I examine the notion of truth in the intuitionistic type theory and provide a better explanation of the objective intuitionistic conception of mathematical truth than that of Dag Prawitz. After a brief explanation of the distinction among proposition, type and judgement in comparison with Frege's theory of judgement, I examine the judgements of the form 'A true' in the intuitionistic type theory and explain how the determinacy of the existence of proofs can be understood intuitionistically. I also examine how the existential judgements of the form 'Pf(A) exists' should be understood. In particular, I diagnose the reason why such existential judgements do not have propositional contents. I criticize an understanding of the existential judgements as elliptical judgements. I argue that, at least in two respects, the notion of truth explained in this paper is a more advanced version of the objective intuitionistic conception of mathematical truth than that provided by Prawitz. I briefly consider a subjectivist's objection to the conception of truth explained in this paper and provide an answer to it.

• The Journal of the Acoustical Society of Korea
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• v.15 no.5
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• pp.65-72
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• 1996

A dynamic self-consistent method previously proposed and validated for the composites containing spherical inclusions is applied to the simplest two dimensional problems : SH wave propagation in unidirectional fiber reinforced composites. The self-consistent conditions for SH wave are derived without limitation on frequency and the wave speed and coherent attenuation are calculated for two composites. THe results of the present theory are compared with those of the multiple scattering theories and another self-consistent theory. At low volume fractions, the present theoretical results coincide with those of the multiple scattering theory using exact pair-correlation function, whereas the results based on another self-consistent theory deviate markedly from the others. As the volume fraction increases, the three theories give different results although they have qualitatively similar trends. The present theoretical results for composites considered in this paper exhibit less dispersion and physically realizable attenuation. An important observation is that the multiple scattering theory predicts vanishingly small attenuation at low frequency with volume fraction is high.

• Korean Journal of Logic
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• v.22 no.3
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• pp.417-446
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• 2019

The operation theory of the Wittgenstein's Tractatus Logico-Philosophicus is the essential basis of the philosophy of mathematics of the Tractatus. Wittgenstein presents the definition of cardinal numbers on the basis of operation theory, and suggests the proof of "$2{\times}2=4$" by using the theory of operations in 6.241. Therefore, in order to explicate correctly the philosophy of mathematics, it is required to understand rigorously the theory of operations in the Tractatus. Accordingly in this paper, I will endeavor to explicate operation theory of the Tractatus as a preliminary study for explicating the philosophy of mathematics of the Tractatus. In this process, we can ascertain Frascolla's important contributions and fallacies in his reconstruction of 6.241. In particular, we can understand the background that in 6.241 Wittgenstein made mistakes and that there he dealt with the addition operation of the theory of operations, and on the basis of this, we can reconstruct correctly 6.241.

• Journal of Gifted/Talented Education
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• v.23 no.5
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• pp.817-833
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• 2013

The study aims to analyze Thomas Young's problem solving processes of analogical reasoning during the formation of the interference theory of light, and to draw its implications for secondary science education, particularly for enhancing creativity in science. The research method employed in the study was literature review of the papers which Young himself had written about sound wave and property of light. His thinking processes and specific features in his thought that were obtained through analysis of his papers about light are as follows: Young reconsidered Newton's experiments and observations, and reinterpreted Newton's results in the new viewpoints. Through this analysis, Young discovered that Newton's interpretation about his own experiments and observations was faulty in a certain point of view and new interpretation is necessary. Based on the data, it is hypothesized that colors observed on thin plates and colors appeared repeatedly on Newton's ring are appeared because of the effect of light interference. Young used analogical reasoning during the process of inference of similarity between sound and light. And he formulated an hypothesis on the interference of light through using abductive reasoning from interference of water wave, and proved the hypothesis by constructing an creative experimental device, which is called a critical experiment. It is implicated that the analogical reasoning and experimental devices for explaining the light interference which Young created and used can be utilized for school science education enhancing creativity in science.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.955-958
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• 2001

본 논문에서는 비동기 CDMA 시스템에서 다중접속에 의한 간섭을 제거하는 역상관기 중에서 반복 연산을 사용하여 계산량을 개선한 second-order stationary 기반의 반복적 역상관기와 수렴특성에 대하여 이론적으로 분석하고 모의실험을 통하여 성능을 검증하였다. 먼저 반복적 역상관기에서 수렴특성을 결정하는 수렴 인자를 유도하고 가장 빠른 수렴 특성을 보장하는 최적의 수렴상수를 상관행렬의 최대 및 최소 고유값으로 나타낼 수 있음을 증명하였다. 또한 최적의 수렴 상수와 반복회수에 따른 BER이 기존의 역상관기와 비슷한 성능을 가짐을 보였다.

• Proceedings of the Technology Innovation Conference
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• 2009.02a
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• pp.475-487
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• 2009

본 연구는 중국 기업들을 대상으로 가치 혁신 신제품개발 전략, 관리 방식, 학습 방식, 그리고 신제품 성과간의 관계를 살펴보고, 중국 고유 문화와 중국이 겪고 있는 환경적 변화가치 혁신 신제품개발을 위한 관리 방식과 학습 방식에 어떻게 영향을 끼치는지를 조사하였다. 본 연구 결과는 이론적으로, 가치 혁신 신제품개발을 위해서는 조합적 관리방식과 조합적 학습 방식이 필요하다는 점을 밝혀 주고 있다. 그리고, 중국 기업들은 이러한 관리와 학습 방식을 수행하는데 유리한 국가 문화와 환경을 갖고 있음을 보여 주고 있기 때문에, 국가 문화와 국가 환경이 신제품개발 관리에 영향을 끼치고 있음을 증명해 주고 있다.