• 한국수학교육학회지시리즈B:순수및응용수학
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• 제5권1호
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• pp.45-54
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• 1998

We study the space-times that have a unique terminal indecomposable past set or a unique terminal indecomposable future set and examine their causal boundary, and we investigate some conditions for the warped product space-times of the form (a, b) ${\times}_fF$ to have a unique terminal indecomposable past set or a unique terminal indecomposable future set.

• 대한수학회논문집
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• 제15권2호
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• pp.349-355
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• 2000

In this paper we generalize the Whitehead theorem which says that a homology equivalence implies a homotopy equivalence for nilpotent spaces. We make some theorems on a homotopy equivalence of non-nilpotent spaces, e.g., the solvable space or space satisfying the condition (T**) or space X with $\pi$1(X) Engel, or locally nilpotent space with some properties. Furthermore we find some conditions that the Wall invariant will be trivial.

• 대한수학회지
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• 제53권5호
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• pp.1037-1056
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• 2016

In this paper, we define the concepts of commute proximally, dominate proximally, weakly dominate proximally, proximal generalized ${\varphi}$-contraction and common best proximity point in probabilistic Menger space. We prove some common best proximity point and common fixed point theorems for dominate proximally and weakly dominate proximally mappings in probabilistic Menger space under certain conditions. Finally we show that proximal generalized ${\varphi}$-contractions have best proximity point in probabilistic Menger space. Our results generalize many known results in metric space.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2009년 춘계학술발표대회 논문집
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• pp.310-315
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• 2009

Current improvements on the standard of living reduced working hours and increased leisure time. Therefore, people's ideas on life style changed and different demands on residential environment are being made. Residents of apartment want a community facility that enables constant exchange with other residents and supports living. Ideas on how to use physical space to strengthen a community is becoming an issue these days. Community facility plays a crucial role in giving a certain characteristic to the whole apartment and improving the image as a community. It also provides a physical environment and induces active participation of community life from apartment residents. The community facility in an important environment for children, which helps them develop in growth and in society as well. Community facility is a space where children fulfill their curiosity and amusement. Since children are greatly influenced by the physical surroundings, community facility for children should not remain as a space for fun but should change into a space for interaction. This study chose six apartments at Dongtan New Town, located in Hwaseong, Kyunggido. This study focuses on the characteristics of design for children's community facility and would like to make a proposal about future space planning for children's community facility.

• 천문학회보
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• 제37권2호
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• pp.121.2-121.2
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• 2012

Several case studies reported that low-latitude Pi2 pulsations can occur under extremely quiet geomagnetic condition (Kp = 0) and that those are not associated with substorms. Until now, no statistical study has investigated Pi2 activity at low latitude during non-substorm intervals. In this study, we statistically examine the properties of Pi2 pulsations (i.e., Pi2 pulsation's power, frequency, and duration) observed at low-latitude Bohyun (BOH, L = 1.35) station in Korea. 161 Pi2s are identified during the intervals of extremely quiet geomagnetic conditions (Kp = 0-1) on November 2008. It is found that their frequencies increase as the solar wind speed increases. It is also found that the Pi2 pulsations frequently occurred periodically every ~30 min. Using solar wind data, we discuss what determines the 30-min recurrence time of Pi2 pulsations

• 한국산학기술학회논문지
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• 제17권11호
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• pp.521-536
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• 2016

천주교의 경우 예배와 기도가 이루어지는 교회건물의 중심은 전례공간이라고 할 수 있다. 이 전례공간의 조성은 참례자의 감성에 영향을 주고, 이 감성은 믿음과 연결되기 때문에 전례공간에서 감성에 대한 고려는 매우 중요한 계획요소가 된다고 할 것이다. 본 연구에서는 감성요소 중 시각을 통해 심성을 변화시키는 데에 가장 중요한 조건을 '빛'이라고 보고, 신심을 불러일으키는 전례공간을 형성하는 데에 빛의 역할을 강조하고자 하였다. 따라서 전례공간의 전례상 의미와 중요성을 이해하고, 공간적 위상과 역할을 파악하였고, 전례공간에서의 빛의 기능적 감성적 특성을 분석하기 위해 빛의 종류와 특성, 빛의 역할과 조건 등과 감성의 대상으로서의 빛에 대해 자료를 분석 정리하였다. 그리고 전례공간에서의 빛의 사용사례의 분석을 통해 그 효과와 적절성 및 적용의 조건 등을 파악하였다. 본 연구를 통해 성당의 사회적 역할 변화가 이루어지고 있고, 빛의 디자인적 역할 강화와 함께 성당공간의 활용도 제고에 따른 인공조명의 연출적용이 필요하게 됨을 확인하게 되었다. 또한 연구자료의 분석을 통해 적정조도의 기준을 제안할 수 있게 되었다. 이러한 과정을 통해 얻어진 결과를 종합하여 전례공간에의 빛요소 적용에 대한 계획적 방안을 제안하고자 하였다.

• Imaging Science in Dentistry
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• 제47권3호
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• pp.199-207
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• 2017

Purpose: Evaluation of alveolar bone is important in the diagnosis of dental diseases. The periodontal ligament space is difficult to clearly depict in cone-beam computed tomography images because the reconstruction filter conditions during image processing cause image blurring, resulting in decreased spatial resolution. We examined different reconstruction filters to assess their ability to improve spatial resolution and allow for a clearer visualization of the periodontal ligament space. Materials and Methods: Cone-beam computed tomography projections of 2 skull phantoms were reconstructed using 6 reconstruction conditions and then compared using the Thurstone paired comparison method. Physical evaluations, including the modulation transfer function and the Wiener spectrum, as well as an assessment of space visibility, were undertaken using experimental phantoms. Results: Image reconstruction using a modified Shepp-Logan filter resulted in better sensory, physical, and quantitative evaluations. The reconstruction conditions substantially improved the spatial resolution and visualization of the periodontal ligament space. The difference in sensitivity was obtained by altering the reconstruction filter. Conclusion: Modifying the characteristics of a reconstruction filter can generate significant improvement in assessments of the periodontal ligament space. A high-frequency enhancement filter improves the visualization of thin structures and will be useful when accurate assessment of the periodontal ligament space is necessary.

• East Asian mathematical journal
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• 제29권5호
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• pp.491-501
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• 2013

This paper is concerned with the necessary conditions of the optimal boundary control for some chemotaxis equations. We obtain the existence and the necessary conditions of the optimal boundary control in the space $(H^1(0,T))^2$. Moreover, under some assumptions, we show the uniqueness of the optimal control.

• Advances in aircraft and spacecraft science
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• 제1권2호
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• pp.197-218
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• 2014

Quite a demanding task frequently arises in space engineering, when dealing with the cargo accommodation of modules and vehicles. The objective of this effort usually aims at maximizing the loaded cargo, or, at least, at meeting the logistic requirements posed by the space agencies. Complex accommodation rules are supposed to be taken into account, in compliance with strict balancing conditions and very tight operational restrictions. The context of the International Space Station (ISS) has paved the way for a relevant research and development activity, providing the company with a remarkable expertise in the field. CAST (Cargo Accommodation Support Tool) is a dedicated in-house software package (funded by the European Space Agency, ESA, and achieved by Thales Alenia Space), to carry out the whole loading of the Automated Transfer Vehicle (ATV). An ad hoc version, tailored to the Columbus (ISS attached laboratory) on-board stowage issue, has been further implemented and is to be used from now on. This article surveys the overall approach followed, highlighting the advantages of the methodology put forward, both in terms of solution quality and time saving, through an overview of the outcomes obtained to date. Insights on possible extensions to further space applications, especially in the perspective of the paramount challenges of the near future, are, in addition, presented.

• 한국조경학회지
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• 제28권5호
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• pp.93-103
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• 2000

This research is to propose a rational criterion of the selection and the management f the roadside trees, and to establish the planting design and system with the objective of improving the roadside environment. All of the roadside trees in each objective courses in Kangnung, and the soil disposition, hardness of the soil in the planting areas have been investigated. Also, we have surveyed the kinds of the trees which kandgnung inhabitants want. The conclusion is as follows Most of roadsides have trees, but they need the introduction of shrubs or ground covering plants according to the locations and the environmental conditions. We have selected nineteen species in regard to the roadside tree criterion and the growing conditions living in Kangnung. It is desirable that we make banding style planting space between each roadside tree to improve the low ratio of green coverage. We have found out that Ligustrum obtusifolium, Buxus micropnylla, Euonymus japonica, Rhododendron schlippenbachii, Phyllostachys nigro and Rosa rugosa, ect. are suitable. In order to soften and weaken the rigidity of the hard substances on a paved roadside, the climbers such as the perennial herbaceous flowering and hedera rhombea should be preferred rather than annual herbaceous flowering because of curtailment of expenditure. To posses a systematical greenery frame in kangnung, we have planned a planting design system that would expand the greenery space every year. Moreover, we have to make a plan to overcome space restrictions. We have established a flexible plan considering the roadside conditions and the improved standard planting methods with an ultimate aim to create a special roadside view.