• The Pure and Applied Mathematics
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• v.25 no.4
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• pp.243-252
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• 2018

In this paper, we study the sequentially open and closed subsets of sequential topological groups determined by sequentially continuous group homomorphism. In particular, we investigate the sequentially openness (closedness) and sequentially compactness of subsets of sequential topological groups by the aid of sequentially continuity, sequentially interior or closure operators. Moreover, we explore subgroup and sequential quotient group of a sequential topological group.

• Journal of the Chungcheong Mathematical Society
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• v.33 no.3
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• pp.365-374
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• 2020

Given a noncompact semisimple Lie group G and its maximal compact Lie subgroup K such that the right multiplication of each element in K gives an isometry on G, consider a principal bundle G → G/K, which is a Riemannian submersion. We study the infinitesimal holonomy isometries. Given a closed curve at eK in the base space G/K, consider the holonomy displacement of e by the horizontal lifting of the curve. We prove that the correspondence is continuous.

• Journal of the Korean Mathematical Society
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• v.47 no.4
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• pp.675-689
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• 2010

For a closed symplectic 4-manifold X, let $Diff_0$(X) be the group of diffeomorphisms of X smoothly isotopic to the identity, and let Symp(X) be the subgroup of $Diff_0$(X) consisting of symplectic automorphisms. In this paper we show that for any finitely given collection of positive integers {$n_1$, $n_2$, $\ldots$, $n_k$} and any non-negative integer m, there exists a closed symplectic (or K$\ddot{a}$hler) 4-manifold X with $b_2^+$ (X) > m such that the homologies $H_i$ of the quotient space $Diff_0$(X)/Symp(X) over the rational coefficients are non-trivial for all odd degrees i = $2n_1$ - 1, $\ldots$, $2n_k$ - 1. The basic idea of this paper is to use the local invariants for symplectic 4-manifolds with contact boundary, which are extended from the invariants of Kronheimer for closed symplectic 4-manifolds, as well as the symplectic compactifications of Stein surfaces of Lisca and Mati$\acute{c}$.

• Archives of Craniofacial Surgery
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• v.17 no.1
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• pp.14-19
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• 2016

Background: Most nasal bone fractures are corrected using non-invasive methods. Often, patients are dissatisfied with surgical outcomes following such closed approach. In this study, we compare surgical outcomes following blind closed reduction to that of ultrasound-guided reduction. Methods: A single-institutional prospective study was performed for all nasal fracture patients (n=28) presenting between May 2013 and November 2013. Upon research consent, patients were randomly assigned to either the control group (n=14, blind reduction) or the experimental group (n=14, ultrasound-guided reduction). Surgical outcomes were evaluated using preoperative and 3-month postoperative X-ray images by two independent surgeons. Patient satisfaction was evaluated using a questionnaire survey. Results: The experimental group consisted of 4 patients with Plane I fracture and 10 patients with Plane II fracture. The control group consisted of 3 patients with Plane I fracture and 11 patients with Plane II fracture. The mean surgical outcomes score and the mean patient dissatisfaction score were found not to differ between the experimental and the control group in Plane I fracture (p=0.755, 0.578, respectively). In a subgroup analysis consisting of Plane II fractures only, surgeons graded outcomes for ultrasound-guided reduction higher than that for the control group (p=0.007). Likewise, among the Plane II fracture patients, those who underwent ultrasound-guided reduction were less dissatisfied than those who underwent blind reduction (p=0.043). Conclusion: Our study result suggests that ultrasound-guided closed reduction is superior to blind closed reduction in those patients with Plane II nasal fractures.

• Journal of Chest Surgery
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• v.20 no.1
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• pp.39-47
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• 1987

The records of 268 patients, who were diagnosed as spontaneous pneumothorax during the period 1975 to 1984, treated at the department of thoracic and cardiovascular surgery, Hanyang University Hospital, were reviewed retrospectively to evaluate the effect of surgical intervention on each indications. Of these,.61 patients [22.8%] were taken operation to treat the pneumothorax after closed thoracostomy. We have classified the 61 patients to evaluate the therapeutic effect on each indications. And the therapeutic effect is based on the chest tube indwelling days. The results were as follows: 1. The chest tube indwelling days of the group who were taken closed thoracostomy only was average 14.13*9.17 days [range 5-66 days], and that of the group who were finally taken the thoracotomy after closed thoracostomy was 21.85*12.30 days [range 5-55 days]. 2. The indications of thoractomy were thoracoscopic findings, recurrence and continuous air leakage. 3. The chest tube indwelling day of the group who was taken thoracotomy by thoracoscopic findings was average 11.67*6.51 day, that was relatively short compared to those of the other groups. 4. The continuous air leakage group after closed thoracostomy was subdivided into three subgroups, continuous air leakage in 1st attack, thoracoscopic findings in 1st attack, and recurrence. 5. Of these, the chest tube indwelling day of the subgroup, who was taken operation by thoracoscopic findings, was 21.33e8.26, that was relatively short compared with those of the other subgroups. We use the thoracoscope as excellent diagnostic tool to detect the operation indication in the spontaneous pneumothorax patients. And we gain the benefits to shorten the chest tube indwelling days and admission days, and also to protect the recurrence.

• Honam Mathematical Journal
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• v.33 no.4
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• pp.557-573
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• 2011

Let G be a compact and connected semisimple Lie group, H a closed subgroup, g (resp. h) the Lie algebra of G (resp. H), B the Killing form of g, g the normal metric on the homogeneous space G/H which is induced by -B. Let D be an invarint connection with Weyl structure (D, g, ${\omega}$) in the tangent bundle over the normal homogeneous Riemannian manifold (G/H, g) which is projectively flat. Then, the affine connection D on (G/H, g) is a Yang-Mills connection if and only if D is the Levi-Civita connection on (G/H, g).

• Bulletin of the Korean Mathematical Society
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• v.45 no.1
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• pp.33-37
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• 2008

Let G be a compact abelian Lie group, and M an odd-dimensional closed smooth G-manifold. If the fixed point set $M^G\neq\emptyset$ and dim $M^G=0$, then G has a subgroup H with $G/H{\cong}\mathbb{Z}_2$, the cyclic group of order 2. The tangential representation $\tau_x$(M) of G at $x{\in}M^G$ is also regarded as a representation of H by restricted action. We show that the number of fixed points is even, and that the tangential representations at fixed points are pairwise isomorphic as representations of H.

• Journal of Chest Surgery
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• v.40 no.4 s.273
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• pp.292-296
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• 2007

Background: This retrospective study was undertaken to assess the effectiveness of the 8-French (Fr) catheter ($Pleuracan^{(R)}$) for the initial treatment of primary spontaneous pneumothorax. Material and Method: Between July 2004 and July 2006, 59 patients (72 cases) underwent a closed thoracostomy for primary spontaneous pneumothorax. We divided these patients into two groups: group T (large bore (>20 Fr) chest tube group) and group P ($Pleuracan^{(R)}$ group). Result: Initially, the $Pleuracan^{(R)}$ catheters were inserted in 41 cases. There were four catheter malfunctions (9.8%) : three cases had a subsequent closed thoracostomy with a large bore chest tube. Ultimately, there were 34 cases in group T and 38 cases in group P. There were no significant differences in indwelling catheter time ($T:\;2.1{\pm}1.5\;days,\;P:\;2.1{\pm}1.3\;days$), hospital stay ($T:\;6.4{\pm}5.4\;days,\;P:\;5.2{\pm}2.9\;days$) and complications (T: 3%, P: 0%) between the two groups. The percentage of cases that needed intravenous analgesics in group P was 60% (23/38); this was significantly lower than the number for group T (90%, 31/34) (p=0.003). In a subgroup of patients that did not undergo bullectomy(T: 17 cases, P: 19 cases), there were no significant differences in the duration of air leakage ($T:\;0.5{\pm}0.7\;days,\;P:\;0.5{\pm}1.2\;days$) and in the percentage of patients with complete lung re-expansion (T: 94%, P: 84%) between the two groups. Conclusion: Application of the $Pleuracan^{(R)}$ catheter for the initial treatment of primary spontaneous pneumothorax was as effective as the large bore chest tube.

• Korean Journal of Heritage: History & Science
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• v.52 no.3
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• pp.172-187
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• 2019

Knowledge of intangible cultural heritage is usually disseminated through word-of-mouth and actions rather than written records. Thus, people assemble to teach others about it and form communities. Accordingly, to understand and spread information about intangible cultural heritage properly, it is necessary to understand not only their attributes but also a community's relational characteristics. Community members include specialized transmitters who work under the auspices of institutions, and general transmitters who enjoy intangible cultural heritage in their daily lives. They converse about intangible cultural heritage in close relationships. However, to date, research has focused only on professionals. Thus, this study focused on the roles of general transmitters of intangible cultural heritage information by investigating intangible cultural heritage communities centering around Jeongseon Arirang; a social network analysis was performed. Regarding the research objectives presented in the introduction, the main findings of the study are summarized as follows. First, there were 197 links between 74 members of the Jeongseon Arirang Transmission Community. One individual had connections with 2.7 persons on average, and all were connected through two steps in the community. However, the density and the clustering coefficient were low, 0.036 and 0.32, respectively; therefore, the cohesiveness of this community was low, and the relationships between the members were not strong. Second, 'Young-ran Yu', 'Nam-gi Kim' and 'Gil-ja Kim' were found to be the prominent figures of the Jeongseon Arirang Transmission Community, and the central structure of the network was concentrated around these three individuals. Being located in the central structure of the network indicates that a person is popular and ranked high. Also, it means that a person has an advantage in terms of the speed and quantity of the acquisition of information and resources, and is in a relatively superior position in terms of bargaining power. Third, to understand the replaceability of the roles of Young-ran Yu, Nam-gi Kim, and Gil-ja Kim, who were found to be the major figures through an analysis of the central structure, structural equivalence was profiled. The results of the analysis showed that the positions and roles of Young-ran Yu, Nam-gi Kim, and Gil-ja Kim were unrivaled and irreplaceable in the Jeongseon Arirang Transmission Community. However, considering that these three members were in their 60s and 70s, it seemed that it would be necessary to prepare measures for the smooth maintenance and operation of the community. Fourth, to examine the subgroup hidden in the network of the Jeongseon Arirang Transmission Community, an analysis of communities was conducted. A community refers to a subgroup clearly differentiated based on modularity. The results of the analysis identified the existence of four communities. Furthermore, the results of an analysis of the central structure showed that the communities were formed and centered around Young-ran Yu, Hyung-jo Kim, Nam-gi Kim, and Gil-ja Kim. Most of the transmission TAs recommended by those members, students who completed a course, transmission scholarship holders, and the general members taught in the transmission classes of the Jeongseon Arirang Preservation Society were included as members of the communities. Through these findings, it was discovered that it is possible to maintain the transmission genealogy, making an exchange with the general members by employing the present method for the transmission of Jeongseon Arirang, the joint transmission method. It is worth paying attention to the joint transmission method as it overcomes the demerits of the existing closed one-on-one apprentice method and provides members with an opportunity to learn their masters' various singing styles. This study is significant for the following reasons: First, by collecting and examining data using a social network analysis method, this study analyzed phenomena that had been difficult to investigate using existing statistical analyses. Second, by adopting a different approach to the previous method in which the genealogy was understood, looking at oral data, this study analyzed the structures of the transmitters' relationships with objective and quantitative data. Third, this study visualized and presented the abstract structures of the relationships among the transmitters of intangible cultural heritage information on a 2D spring map. The results of this study can be utilized as a baseline for the development of community-centered policies for the protection of intangible cultural heritage specified in the UNESCO Convention for the Safeguarding of Intangible Cultural Heritage. To achieve this, it would be necessary to supplement this study through case studies and follow-up studies on more aspects in the future.