• 대한수학회논문집
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• 제34권1호
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• pp.279-286
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• 2019

Complex Grassmann manifolds $G_{n,k}$ are a generalization of complex projective spaces and have many important features some of which are captured by the $Pl{\ddot{u}}cker$ embedding $f:G_{n,k}{\rightarrow}{\mathbb{C}}P^{N-1}$ where $N=\(^n_k\)$. The problem of existence of cross sections of fibrations can be studied using the Gottlieb group. In a more generalized context one can use the relative evaluation subgroup of a map to describe the cohomology of smooth fiber bundles with fiber the (complex) Grassmann manifold $G_{n,k}$. Our interest lies in making use of techniques of rational homotopy theory to address problems and questions involving applications of Gottlieb groups in general. In this paper, we construct the Sullivan minimal model of the (complex) Grassmann manifold $G_{n,k}$ for $2{\leq}k<n$, and we compute the rational evaluation subgroup of the embedding $f:G_{n,k}{\rightarrow}{\mathbb{C}}P^{N-1}$. We show that, for the Sullivan model ${\phi}:A{\rightarrow}B$, where A and B are the Sullivan minimal models of ${\mathbb{C}}P^{N-1}$ and $G_{n,k}$ respectively, the evaluation subgroup $G_n(A,B;{\phi})$ of ${\phi}$ is generated by a single element and the relative evaluation subgroup $G^{rel}_n(A,B;{\phi})$ is zero. The triviality of the relative evaluation subgroup has its application in studying fibrations with fibre the (complex) Grassmann manifold.

• 대한수학회논문집
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• 제36권4호
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• pp.835-840
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• 2021

In this paper, we compute the rational evaluation subgroup of the Hopf fibration S²ⁿ⁺¹ ↪ ℂP(n). We show that, for the Sullivan model 𝜙 : A → B, where A and B are the minimal Sullivan models of ℂP(n) and S²ⁿ⁺¹ respectively, the evaluation subgroup G_n(A, B; 𝜙) and the relative evaluation subgroup G^rel_n (A, B; 𝜙) of 𝜙 are generated by single elements.

• 대한수학회보
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• 제27권2호
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• pp.121-126
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• 1990

• 대한수학회논문집
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• 제12권3호
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• pp.709-715
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• 1997

For a fibration (E,B,p) with fiber F and a fiber map f, we show that if the inclusion $i : F \to E$ has a left homotopy inverse, then $G^f_n(E,F)$ is isomorphic to $G^f_n(F,E) \oplus \pi_n(B)$. In particular, by taking f as the identity map on E we have $G_n(E,F)$ is isomorphic to $G_n(F) \oplus \pi_n(B)$.

• 대한수학회논문집
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• 제11권1호
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• pp.235-244
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• 1996

For a self-map f of a CW-pair (X, A), we introduce the G(f)-sequence of (X, A) which consists of subgroups of homotopy groups in the homotopy sequence of (X, A) and show some properties of the relative homotopy Jian groups. We also show a condition for the G(f)-sequence to be exact.

• 충청수학회지
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• 제18권1호
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• pp.23-31
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• 2005

In this paper, we observe the relation between the concept of generalized Gottlieb groups and the Hurewicz homomorphism.

• 대한수학회보
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• 제50권5호
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• pp.1725-1736
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• 2013

In this paper, we compute the images of homotopy groups of various classical Lie groups under the homomorphisms induced by the natural projections from those groups to irreducible symmetric spaces of classical type. We identify that those computations are certain lower bounds of Gottlieb groups of irreducible symmetric spaces. We use the lower bounds to compute some Gottlieb groups.

• 디지털산업정보학회논문지
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• 제17권1호
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• pp.75-84
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• 2021

For analyzing big data, the social network is increasingly being utilized through relational data, which means the connection characteristics between entities such as people and objects. When the relational data does not exist directly, a social network can be configured by calculating relational data such as attribute similarity from attribute data of entities and using it as links. In this paper, the composition method of the social network using the attribute similarity between entities as a connection relationship, and the clustering method using subgroups for the configured social network are suggested, and the clustering effectiveness of the clustering results is evaluated. The analysis results can vary depending on the type and characteristics of the data to be analyzed, the type of attribute similarity selected, and the criterion value. In addition, the clustering effectiveness may not be consistent depending on the its evaluation method. Therefore, selections and experiments are necessary for better analysis results. Since the analysis results may be different depending on the type and characteristics of the analysis target, options for clustering, etc., there is a limitation. In addition, for performance evaluation of clustering, a study is needed to compare the method of this paper with the conventional method such as k-means.

• 생명과학회지
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• 제30권1호
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• pp.1-9
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• 2020

키위 세균성 궤양병의 원인균인 Pseudomonas syringae pv. actinidiae는 유전적으로 구별되는 다섯 개의 biovar (1, 2, 3, 5, 6)로 나뉘어 진다. 그 중 biovar 3에 속하는 균주가 2008년 이래 전세계적으로 대유행을 일으키고 있다. 본 연구의 목표는 우리나라에서 분리된 biovar 3균주들의 집단 구조를 밝히고 그들의 기원을 추적하는데 있다. 13개의 우리나라 대표 균주와 2개의 중국 균주를 포함하는 15개 biovar 3 균주의 유전적 다양성을 RAPD-PCR로 평가하였다. RAPD 결과 연구에 사용된 균주들은 8개로 나누어져 이들을 subgroup I - VIII로 명명하였다. Subgroups II와 III은 중국 균주로 우리나라에서 발견되지 않았다. 따라서 우리나라 biovar 3 균주는 유전적으로 구별되는 6개의 subgroup (I, IV, V, VI, VII, VIII)으로 구성되어 있음을 알 수 있었다. New Zealand와 Europe균주에 특이적인 각각의 프라이머를 사용하여 PCR을 수행했을 때 subgroups V와 VI에 속하는 균주가 예상했던 DNA 절편을 증폭시켜 이들이 각각 두 지역에서 유입된 균주임을 시사하였다. 우리나라에서 처음 발견된 biovar 3 균주인 subgroup VIII에 특이적인 프라이머를 개발하여 조사한 결과 이 subgroup 균주는 처음 출현한 이후 더 이상 발견되지 않았다.

• 한방안이비인후피부과학회지
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• 제35권3호
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• pp.48-65
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• 2022

Objectives : This study was conducted to find out the effectiveness and safety of herbal medicine eye drops on conjunctivitis. Methods : We searched randomized controlled trials on conjunctivitis through 10 DBs from the start to April 27, 2022. Study collection and data extraction, and evaluation of risk of bias were conducted by two independent researchers. The evaluation of the risk of bias in included RCTs was carried out by using Cochrane risk-of-bias tool. And the data synthesis was conducted by using Review Manager(RevMan, ver.5.4). Results : Total of 106 studies are researched and 7 studies of them are finally included. 1. The herbal medicine eye drops are more effective on than the western medicine eye drops, but the heterogeneity was very high. So we conducted sensitivity analysis and compared to the herbal medicine eye drops and the western medicine eye drops, the total effective rate was higher in the herbal medicine eye drops and the heterogeneity was somewhat reduced. 2. In the subgroup analysis, Fufang Xiongdan eye drops and Houttuynia cordata Thunb eye drops are more effective than the western medicine. It may represent substantial heterogeneity. 3. In the subgroup analysis, the herbal medicine eye drops are more effective than antibiotic and antiviral eye drops on acute bacterial conjunctivitis, but showed high heterogeneity. On the other hand, the herbal medicine eye drops are more effective than antibiotic and antiviral eyed drops on acute viral conjuctivitis and showed low heterogeneity. 4. In the subgroup analysis, we compared the effectiveness of herbal and western medicine eye drops according to total effectiveness rate evaluation methods. When comparing the studies calculating the total effective rate by the sum of 'Cured', 'Significantly Impaired', and 'Improved', the effective rate of the herbal medicine eye drops was higher than that of the western medicine eye drops, and the heterogeneity was very low. 5. In most studies, side effects of herbal medicine eye drops were absent or mild. Conclusions : This study shows that herbal medicine eye drops may be more effective than western medicine eye drops and have safety. But further researches are needed to resolve the heterogeneity of this study.