• 호남수학학술지
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• 제1권1호
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• pp.27-34
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• 1979

근래(近來) Skorokhod는 확률론(確率論)의 극한문제(極限問題)와 관련(關聯)하여 모든 불연속함수공간(不連續函數空間)에 관(關)한 위상(位相)을 정의(定義)하였다. 본(本) 논문(論文)에서는 Skorokhod 수렴위상(收斂位相)을 쌍위상(雙位相)(bitopology)형(型)으로 일반화(一般化)하고 잘 알려져 있는 여러위상(位相)과 비교(比較)하여 다음과 같은 결과(結果)를 새로 얻었다. (정리(定理) 2-11); 공간(空間) X와 Y가 완비준거이가분공간(完備準距離可分空間) (Completdy quasi-metric separable space)이라면 쌍개수렴위상(雙槪收斂位相)(pairwise almost convergent topology)는 Skorokhod 쌍수렴위상(雙收斂位相) 보다 약(弱)하다. 그리고 (정리(定理) 2-12); 쌍(雙) graph 위상(位相)은 Skorokhod $J_1$-수렴위상(收斂位相)과 일치(一致)한다. 끝으로 주정리(主定理)인 (정리(定理( 3-1)과 (정리(定理) 3-2)에서 Skorokhod 쌍수렴위상(雙收斂位相)의 Compact성(性)에 관(關)한 필요충분조건(必要充分條件)을 밝혔다.

• 산업경영시스템학회지
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• 제30권1호
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• pp.41-47
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• 2007

Mahalanobis Taguchi-System (MTS) is a pattern information technology, which has been used in different diagnostic ap plications to make quantitative decisions by constructing a multivariate system using data analytic methods without any as sumption regarding statistical distribution. MTS performs Taguchi's fractional factorial design based on the Mahalanobis distance as a performance metric In this work, MTS used for analyzing automotive brake feeling system, which measured as a brake feel index (BFI) from 9 attributes. The automobile which has a good BFI score treated as a normal group for constructing Mahalanobis space. The results of this research show that two attributes (Pre load & Max deceleration) have a minus gain value and can be removed from further analysis. The difference of MD value between using all 9 attributes and just using significant attribute compared.

• 한국지능시스템학회논문지
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• 제14권1호
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• pp.33-38
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• 2004

이 논문에서는 Schmeidler[14]와 Narukawa[12]에 나오는 보단조 가법 실수치 범함수 개념의 일반화인 보단조 가법 구간치 범함수를 정의하고 그들의 성질을 연구한다. 또한 보단조 가법 구간치 범함수와 구간치 쇼케이적분이 적당한 함수공간 상에서 서로간의 관계를 조사한다. 수의 값을 갖는 함수들의 쇼케이적분을 생각하고자 한다. 이러한 구간 수의 값을 갖는 함수들의 성질들을 조사한다.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2010년도 한국컴퓨터종합학술대회논문집 Vol.37 No.1(C)
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• pp.271-274
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• 2010

한글 근사 단어 검색 시스템은 사용자의 오류를 포함한 검색 질의에 효과적으로 대응할 수 있는 방법이나 검색 속도가 매우 느려서 실제 사용에 큰 어려움이 있다. 일반적으로 DNA 검색에 사용하는 서열 정렬 기법을 사용할 경우 데이터 베이스의 모든 문자열과 비교가 이루어져야 하기 때문에 많은 검색 시간이 걸리게 된다. 이것을 해결하기 위해 우리는 편집거리가 metric space를 만족하는 성질을 이용한 한글 근사단어 검색 시스템을 사용하여 실제 서열정렬을 사용하여 비교가 필요한 후보 단어를 거르게 된다. 이 한글 근사 단어 검색 시스템에서 가장 중요한 것은 기준축의 역할을 하는 Base-Pivot의 선택 방법이다. 본 논문에서는 이 Base-Pivot의 효율적인 선택방법을 실험을 통해서 분석하도록 한다.

• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 2007년도 추계학술대회
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• pp.602-609
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• 2007

Combining collaborative filtering with some other technique is most common in hybrid recommender systems. As many recommended items from collaborative filtering seem to be similar with respect to content, the collaborative-content hybrid system suffers in terms of quality recommendation and recommending new items as well. To alleviate such problem, we have developed a novel method that uses a diversity metric to select the dissimilar items among the recommended items from collaborative filtering, which together with the input when fed into content space let us improve and include new items in the recommendation. We present experimental results on movielens dataset that shows how our approach performs better than simple content-based system and naive hybrid system

• 대한수학회지
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• 제56권1호
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• pp.53-65
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• 2019

Recently, Chung and Lee [2] introduced the notion of topological stability for a finitely generated group action, and proved a group action version of the Walters's stability theorem. In this paper, we introduce the concepts of continuous shadowing and continuous inverse shadowing of a finitely generated group action on a compact metric space X with respect to various classes of admissible pseudo orbits and study the relationships between topological stability and continuous shadowing and continuous inverse shadowing property of group actions. Moreover, we introduce the notion of structural stability for a finitely generated group action, and we prove that an expansive action on a compact manifold is structurally stable if and only if it is continuous inverse shadowing.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제26권3호
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• pp.111-131
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• 2019

We introduce (CLRg) property for hybrid pair $F:X{\times}X{\rightarrow}2^X$ and $g:X{\rightarrow}X$. We also introduce joint common limit range (JCLR) property for two hybrid pairs $F,G:X{\times}X{\rightarrow}2^X$ and $f,g:X{\rightarrow}X$. We also establish some common coupled fixed point theorems for hybrid pair of mappings under generalized (${\psi},{\theta},{\varphi}$)-contraction on a noncomplete metric space, which is not partially ordered. It is to be noted that to find coupled coincidence point, we do not employ the condition of continuity of any mapping involved therein. As an application, we study the existence and uniqueness of the solution to an integral equation. We also give an example to demonstrate the degree of validity of our hypothesis. The results we obtain generalize, extend and improve several recent results in the existing literature.

• 천문학회보
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• 제44권1호
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• pp.56.1-56.1
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• 2019

The concordance LCDM model has been very successful at reproducing a wide range of observations. However, the nature of its main components, such as dark energy, dark matter, and inflation, are still unkown. Therefore, it is of prime importance to question the underlying hypotheses of the model and tests there prediction. While most constraints have been obtained assuming a LCDM universe, model-independent approaches, which do not make assumptions regarding the model, are a powerful approach. To falsify the LCDM model, I applied model-indepedent methods to the latests available data to test different aspects of the concordance model, such as the FLRW metric, the curvature, dark energy as the cosmological constant, and gravity as general relativity. The Universe is consistent with flat-LCDM with GR. However, at z>1, tensions start to appear, and more data are required.

• 대한수학회지
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• 제60권2호
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• pp.255-271
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• 2023

In this paper, we deal with random attractors for dynamical systems forced by a deterministic noise. These kind of systems are modeled as skew products where the dynamics of the forcing process are described by the base transformation. Here, we consider skew products over the Bernoulli shift with the unit interval fiber. We study the geometric structure of maximal attractors, the orbit stability and stability of mixing of these skew products under random perturbations of the fiber maps. We show that there exists an open set U in the space of such skew products so that any skew product belonging to this set admits an attractor which is either a continuous invariant graph or a bony graph attractor. These skew products have negative fiber Lyapunov exponents and their fiber maps are non-uniformly contracting, hence the non-uniform contraction rates are measured by Lyapnnov exponents. Furthermore, each skew product of U admits an invariant ergodic measure whose support is contained in that attractor. Additionally, we show that the invariant measure for the perturbed system is continuous in the Hutchinson metric.

• Nonlinear Functional Analysis and Applications
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• 제28권3호
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• pp.831-850
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• 2023

Our long-standing Metatheorem in Ordered Fixed Point Theory is applied to some well-known order theoretic fixed point theorems. In the first half of this article, we introduce extended versions of the Zermelo fixed point theorem, Zorn's lemma, and the Caristi fixed point theorem based on the Brøndsted-Jachymski principle and our 2023 Metatheorem. We show some of their applications to other fixed point theorems or theorems on the existence of maximal elements in partially ordered sets. In the second half, we collect and improve order theoretic fixed point theorems in the collection of Howard-Rubin in 1991 and others. In fact, we improve or extend several ordering principles or fixed point theorems due to Brézis-Browder, Brøndsted, Knaster-Tarski, Tarski-Kantorovitch, Turinici, Granas-Horvath, Jachymski, and others.