• The Mathematical Education
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• v.43 no.4
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• pp.381-390
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• 2004

In this study, we conceptualized the ‘preformal proof’, which is a transitive level of proof from the experimental and inductive justification to the formalized mathematical proof. We investigated concrete features of the preformal proof in the historico-genetic and the didactical situations. The preformal proof can get the generality of the contents of proof, which makes a distinction from the experimental proof. And we can draw a distinction between the preformal and formal proof, in point that the preformal proof heads for the reality-oriented objects and does not use the formal language.

• English Language & Literature Teaching
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• v.15 no.4
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• pp.199-216
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• 2009

This study investigates how Korean speakers develop their interlanguage of English passive constructions with a reference to the learners' grammar proficiency levels. Sixty two college students of different levels of English participated in this study. They were asked to complete a sentence-completion task. Their production was classified into accurate passives, malformed passives, pseudo-passives, unaccusatives, and actives according to the use of transitive, ergative and unergative verbs. They then were further analyzed depending on the subjects' levels of grammar by three main factors: L1 transfer, the English voice system, and universal cognitive factors. The results showed that the subjects of the lower group produced more pseudo-passives, malformed passives, and overpassivization than those of the higher group, and even subjects of higher group still made passives for ergative verbs. It was also shown that L1 and universal factors had more influence on the lower group than on the higher group. Based on the analyses of the subjects' responses, the development of the English passive system by Korean learners is shown and some implications are suggested for effective teaching of English.

• Kyungpook Mathematical Journal
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• v.58 no.3
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• pp.489-494
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• 2018

The first purpose of this note is to generalize two nice theorems of H. J. Kim concerning hyperinvariant subspaces for certain classes of operators on Hilbert space, proved by him by using the technique of "extremal vectors". Our generalization (Theorem 1.2) is obtained as a consequence of a new theorem of the present authors, and doesn't utilize the technique of extremal vectors. The second purpose is to use this theorem to obtain the existence of hyperinvariant subspaces for a class of $2{\times}2$ operator matrices (Theorem 3.2).

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.05a
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• pp.307-310
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• 2000

소프트웨어의 측정값에 근거하여 소프트웨어 품질에 관한 의사결정을 할 때, 동치관계의 요구조건인 추이적(transitive) 특성이 항상 만족되는 것은 아니다. 순환수(cyclomatic number)가 거의 비슷한 프로그램에서, 하나는 "구조적인" 프로그램 범주에 속하고 또 다른 하나는 비구조적인 프로그램 범주에 속한다고 명확히 분류 할 수 있는가하는 점이다. 따라서, 본 연구에서는 동치관계보다는 허용적 관계를 만족하는 허용적 러프집합에 근거한 소프트웨어 분류 기준 제시하고자 한다. 분류기준을 생성하기 위한 실험 데이터 집합을 수집하고, 집합 내의 각 원소에 관한 허용적 클래스들을 생성한 후, 각 허용적 클래스들의 중심값을 클러스터링하여 분류기준을 생성한다. 생성된 분류기준을 또 다른 실험 집합에 적용하여 비교 분석하여 생성된 분류기준이 타당함을 보여준다.

• The Transactions of the Korea Information Processing Society
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• v.1 no.4
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• pp.461-468
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• 1994

This paper describes the automatic extraction of collocations based on corpus. The collocations are extracted from corpus using cooccurrence frequency and mutual information between words. In English, 5 types of collocations are defined. These collocations are transitive verb and object, intransitive verb and subject, adjective and noun, verb and adverb, and adverb and adjective. In this paper another type of collocation is recognized and extracted, which consists of verb and preposition. So 6 types of collocations are extracted based on corpus.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05c
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• pp.1697-1700
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• 2003

유연생산 시스템에서 스케줄링 문제는 기본적으로 조합 최적화 문제로서 NP-hard problem 으로 알려져 있으며 문제의 크기에 따라 복잡도가 지수적으로 증가하게 된다. 이러한 복잡도를 줄이기 위해 우리는 넷의 행위적인 속성에 따른 제어 흐름들의 집합을 병행적 기본 단위(BUC)로 정의하고, 이들을 종합화함으로 최종적인 스케즐링을 얻게 된다. 본 연구에서는 이러한 병행적 기본 단위로 넷을 분할하여 스케줄링을 분석하는 알고리즘을 제안한다.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.7
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• pp.1-13
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• 1993

In this paper, the problems of the conventional special-purpose array processor such as the deficiency of flexibility have been investigated. Then, a new modified methodology has been suggested and applied to obtain the common solution of the three typical App algorithms like SP(Shortest Path), TC(Transitive Closure), and MST(Minimun Spanning Tree) among the various APP algorithms using the similar method to obtain the solution. In the newly proposed APP parallel algorithm, real-time Processing is possible, without the structure enhancement and the functional restriction. In addition, we design 2-demensional bit-parallel low-triangular systolic array processor and the 1-PE in detail. For its evaluation, we consider its computational complexity according to bit-processing method and describe relationship of total chip size and execution time. Therefore, the proposed processor obtains, on which a large data inputs in real-time, 3n-4 execution time which is optimal o(n) time complexity, o(n$^{2}$) space complexity which is the number of total gate and pipeline period rate is one.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11c
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• pp.1787-1790
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• 2003

기존의 UNIX/LINUX 시스템에서는 setuid 가 걸린 프로그램의 취약점을 공격하여 슈퍼유저(root) 권한을 획득하는 공격이 일반적이다. 본 논문에서는 RBAC 기반 보안 OS 에서도 이와 유사한 권한전이 공격이 가능한지를 실험한다. 또한 논리적 접근통제가 강화된 보안 OS 서 권한 전이 공격에 대해 대응하는 기술에 대하여 고찰한다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.11 no.3
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• pp.65-75
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• 2007

A graph G is self-complementary (sc) if it is isomorphic to its complement. G is perfect if for all induced subgraphs H of G, the chromatic number of H (denoted ${\chi}$(H)) equals the number of vertices in the largest clique in H (denoted ${\omega}$(H)). An sc graph which is also perfect is known as sc perfect graph. A comparability graph is an undirected graph if it can be oriented into transitive directed graph. An sc comparability (scc) is clearly a subclass of sc perfect graph. In this paper we show that no two non-isomorphic scc graphs with n vertices each, (n<13) have same spectrum, and that the smallest positive integer for which there exists hyper-energetic scc graph is 13.

• Communications of the Korean Mathematical Society
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• v.27 no.2
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• pp.369-375
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• 2012

In this article, we focus on certain dynamic phenomena in volume-preserving manifolds. Let $M$ be a compact manifold with a volume form ${\omega}$ and $f:M{\rightarrow}M$ be a diffeomorphism of class $\mathcal{C}^1$ that preserves ${\omega}$. In this paper, we do not assume $f$ is $\mathcal{C}^1$-generic. We prove that $f$ satisfies the chain transitivity and we also show that, on $M$, the $\mathcal{C}^1$-stable shadowability is equivalent to the hyperbolicity.