• Structural Engineering and Mechanics
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• 제60권2호
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• pp.271-299
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• 2016

In this article, based on the higher-order shear deformation plate theory, buckling analysis of a rectangular plate made of functionally graded piezoelectric materials and its effective parameters are investigated. Assuming the transverse distribution of electric potential to be a combination of a parabolic and a linear function of thickness coordinate, the equilibrium equations for the buckling analysis of an FGP rectangular plate are established. In addition to the Maxwell equation, all boundary conditions including the conditions on the top and bottom surfaces of the plate for closed and open circuited are satisfied. Considering double sine solution (Navier solution) for displacement field and electric potential, an analytical solution is obtained for full simply supported boundary conditions. The accurate buckling load of FGP plate is presented for both open and closed circuit conditions. It is found that the critical buckling load for open circuit is more than that of closed circuit in all loading conditions. Furthermore, it is observed that the influence of dielectric constants on the critical buckling load is more than those of others.

• 대한수학회논문집
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• 제26권2호
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• pp.297-304
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• 2011

In this paper, we introduce closure operators [${\cdot}$]c and [${\cdot}$]a on a space and study some relations among [${\cdot}$]c, [${\cdot}$]a and countable tightness. We introduce the concepts of a strongly sequentially closed set and a strongly sequentially open set and show that a space X has countable tightness if and only if every strongly sequentially closed set is closed if and only if every strongly sequentially open set is open. Finally we find a generalization of the weak Fr$\'{e}$chet-Urysohn property which is equivalent to countable tightness.

• 호남수학학술지
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• 제30권2호
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• pp.283-297
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• 2008

The notion of IVF contra (${\alpha}$-)open ((${\alpha}$-)closed) mappings is introduced, and their characterizations are given. The relationship between IVF contra open (closed) mappings and IVF contra ${\alpha}$-open (${\alpha}$-closed) mappings are discussed.

• 복식
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• 제54권4호
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• pp.145-156
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• 2004

This study is regarding closed and open forms, which have relatively high recognition among visual perception phenomena in costumes. In particular, this study reviewed closeness and openness of ethnic look, which is a representative open costume. Closed form can be summarized as simple and clear silhouette, conspicuous differentiation from the background, simple construction of the costume and colors with low brightness and clearness. It Is modern, functional, rational and modest. On the other hand, open form can be summarized as complicated and inconspicuous edge line, complicated inner shape and colors with high brightness, high clearness and vividness. It includes concepts of pleasure, entertainment, joy, eroticism, rebel and resistance. Modern costumes have been simplified for a long time and they have functional and closed characteristics in their shape, structure and form. On the other hand, modern open form costumes are usually found in sub-cultural styles such as punk, hippie, kitsch and vintage, and some ethnic looks. Following is a summary of the characteristics of open form shown in the ethnic look. 1. The shape, structure of costumes, hair accessories, lace, ruffle and ornaments are complicated and irregular. 2. The silhouette is inconspicuous because of ambiguity between backgrounds and ABC (Apparel-Body-Construct) or the use of see-through materials. 3. It makes complicated visual shapes because it does not have a single type but is composed of various clothing items together. 4. It gives complex feelings by matching various colors or more than two different fabrics. 5. It looks like the open type because of the complex patterns shown in the costumes.

• Bulletin of the Korean Chemical Society
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• 제10권3호
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• pp.238-242
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• 1989

The relations between the repulsive interactions and the electron density overlaps are investigated for various closed shell-closed shell pairs, including the systems containing alkali and halide ions. It is found that the repulsive interaction($V_{rep}$) depends on the overlap of the electron density($S_{\rho}$) according to a simple exponential relation, $V_{rep}$ = $As_{\rho}\;^{\alpha}$. Furthermore, for most of the closed shell systems the $\alpha$ values are near unity and the A values do not vary much. The same tests are also performed for the open shell-closed shell, and the open shell-open shell pairs. Although the results for these systems also show exponential dependences of the repulsive interactions on the density overlaps, the details of the dependence differ greatly from those for the closed shell systems and also vary widely from one individual system to another.

• 대한물리의학회지
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• 제9권2호
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• pp.223-231
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• 2014

PURPOSE: The aim of this study was to investigate the effect of closed and open kinetic exercises on knee extensor strength and balance in patients with early stroke. METHODS: Thirty patients with early stroke participated in the study. Participants were randomly assigned to three groups: an open kinetic chain (OKC) exercise group (n=10), a closed kinetic chain (CKC) exercise group (n=10), and a control group (n=10). All participants received conventional physical therapy for 30 minutes. In addition, the two experimental groups (OKC and CKC) participated in a 30-minute knee strengthening training program. Training for the experimental groups was carried out three times a week for four weeks. Outcomes such as knee extensor strength and balance ability (Tetrax, Functional Reaching Test, Timed Up and Go Test) were measured before and after training. RESULTS: There were significant differences in knee extensor strength and balance ability between the pre- and post-treatment of all groups (p<.05). The improvement of knee extensor strength was significantly higher in the OKC group than in the other groups (p<.05), and the improvement of dynamic balance was significantly higher in the CKC group than in the other groups (p<.05). CONCLUSION: These results showed that both open and closed kinetic chain exercises are effective in the improvement of knee extensor strength and balance ability. This study suggests that open and closed kinetic exercise training is an effective training for strength and balance in patients with early stroke.

• 대한물리의학회지
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• 제8권3호
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• pp.369-378
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• 2013

PURPOSE: The purpose of present study was to ascertain how the activity of the serratus anterior muscle, the upper trapezius muscle and the pectoral major muscle was affected while the upper arm was being flexed at 70, 90 and 110 degrees respectively in a closed kinetic chain exercise (wall push up plus) and an open kinetic chain exercise (static hug). METHODS: Sixteen healthy young men subjects participated in the study. Surface electromyography (EMG) data were collected from the dominant-side muscles during a closed kinetic chain exercise and an open kinetic chain exercise. The activity of each muscle was measured quantitatively, and by the use of the two-way repeated ANOVA, the data were compared with each other according to exercises and shoulder flexion angles. RESULTS: Results indicated that the closed kinetic chain exercise did not interact with the open kinetic chain exercise (p>.05). In both the closed kinetic chain exercise and the open kinetic chain exercise, the activity of the serratus anterior muscle became different significantly according to angles (p<.05). Its activity increased in order of 70, 90 and 110 degrees (p<.05). In both exercises and all angles, muscle activity was significantly higher in the serratus anterior muscle than in the upper trapezius muscle and the pectoral major muscle (p<.05). CONCLUSION: The above results show that there is a need to selectively control the exercise stress of the serratus anterior muscle in the case of the patients with the shoulder impingement syndrome characterized by the winged scapula, insufficient scapular protraction and upward rotation.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제6권3호
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• pp.255-263
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• 2006

In this paper, we introduce the concepts of ${\gamma}$-fuzzy feebly open and ${\gamma}$-fuzzy feebly closed sets in Sostak's fuzzy topological spaces and by using them, we explain the notions of ${\gamma}$-fuzzy F-closed spaces. Also, we give some characterization of ${\gamma}$-fuzzy F-closedness in terms of fuzzy filterbasis and ${\gamma}$-fuzzy feebly-${\theta}$-cluster points.

• 한국위성정보통신학회논문지
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• 제6권2호
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• pp.26-34
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• 2011

저전력으로 옥내 고품질의 통신환경을 제공하는 펨토셀에는 등록된 유저만 접근이 가능한 Closed Access mode와 모두에게 접근을 허락한 Open Access mode, 이렇게 대표적으로 두 가지의 접근 모드가 있다. 본 논문에서는 두 접근 방식의 펨토셀이 혼재된 LTE 기반의 OFDMA 셀룰라 환경에서 유저 간의 성능 차이를 완화하고, 시스템 전체의 성능을 향상시키는 접근 모드에 따른 자원 분배를 제안한다. 상대적으로 Closed Access mode보다 다른 유저들에게 고품질의 통신 환경을 제공하는 Open Access mode 펨토셀에게 더 많은 무선 자원을 허용한다. 무선 자원을 더 많이 허용하면 Open Acees mode 펨토셀을 사용하는 유저의 성능은 향상하지만 동시에 다른 유저에게 미치는 간섭 또한 증가하기 때문에 이러한 trade-off 관계를 고려한 최적의 자원 할당이 필요하다. 따라서 시스템 레벨 시뮬레이션을 통해서 최적의 자원 할당 값을 구하고 기존 방식과 최적 값을 적용한 제안한 방식을 시뮬레이션 한 결과, 제안한 방식이 기존 방식보다 전체적인 셀 성능을 향상 되는 것을 볼 수 있었다.

• 한국산림과학회지
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• 제86권1호
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• pp.9-16
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• 1997

최근 들어 contingent valuation method는 산림휴양자원과 같은 비시장재(非市場財)(nonmarket goods)의 경제적 가치평가에 널리 이용되고 있다. 이 방법에는 개방형(open-ended) 질문과 폐쇄형(closed-ended) 질문이 사용되어지는데, 어느 것이 경제적 가치를 적절히 평가하느냐에 관한 결론적 증거는 없다. 따라서 본 연구는 최근 산림휴양활동중 그 수요가 급격히 증가하는 겨울철 야외스포츠인 스키를 사례로 하여 무주리조트 스키장의 방문객들에게 개방형과 폐쇄형질문을 실시하여 두 설문기법간의 추정결과에 차이가 있는 지를 비모수적검정(非母數的檢定)(nonparametric test)을 통하여 검토하고자 수행되었다. 지금까지 외국에서 개발된 여러 비시장재(非市場財)의 가치평가 모형을 적용하여 경제적 가치를 계량화(計量化)한 결과, 무주리조트 스키장을 이용하는 방문자 한 사람당 순경제적편익(純經濟的便益)은 15,131원에서 25,332원까지 나타났으며, 폐쇄형질문을 적용한 순경제적가치(純經濟的價値)가 개방형질문보다도 약 1.15배에서 1.67배까지 높게 나타났다. 비모수적검정(非母數的檢定) 결과 두 질문형태간에는 유의성이 있는 것으로 나타났다. 그 이유로는 폐쇄형질문이 개방형질문보다 전략적 편의(strategic behavior bias)의 발생을 줄일 수 있는 것으로 사료되나, 본 연구 결과로서는 폐쇄형 질문이 개방형 질문보다 더 효율적이라는 증거는 찾을 수 없었다. 따라서 contingent valuation을 이용하여 비시장재(非市場財)의 경제적 가치를 측정할 경우, 이 두 가지의 질문형태를 함께 고려하여 경제적 가치를 결정해야할 것으로 판단된다.