• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.131.1-131.1
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• 2012

We use three-dimensional magnetohydrodynamic (MHD) simulations of flux emergence from solar subsurface to corona. In our previous work, we reported the relation between magnetic-field configuration and the flux expansion factor. Following these results, we investigate where an upflow is generated in an active region and how its location is related to the flux expansion factor. We also derive physical quantities of a real active region from observation data provided by Nobeyama Radioheliograph (NoRH), X-Ray Telescope (XRT), and Extreme Ultraviolet Imaging Spectrometer (EIS) onboard Hinode. These physical quantities are plasma density, temperature and flow. By comparing the simulation result and observational one, we will discuss the properties of the location producing a solar wind.

• Bulletin of the Korean Space Science Society
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• 2002.05b
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• pp.26.1-26
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• 2002

• Land and Housing Review
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• v.2 no.3
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• pp.259-268
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• 2011

Space extension and the increase of the number of households are helpful to raise business value of the remodeling through the renovation of apartment houses that is required by residents of new cities and large-scaled apartment. However, in the case of accepting this demand, it could have a bad influence on the landscape of a complex in terms of the structure of apartment houses and the safety of construction and urban planning, and a problem occurs in the aspect of fairness for reconstruction. For the study, the current status related to the remodeling system through laws, related articles since 2000 and research data was analyzed. In addition, the individual quantitative analysis was conducted in the four aspects to judge whether households expansion for remodeling is plausible:1) Statistical data to comprehend the changes of population and social structure 2) Survey data of floor space index and the building-to-land ratio of new cities at the intial stage for the review of the effect of architectural planning and urban environment 3) Surveys of experts on structural safety in order to judge whether the demand of expansion is accepted or not. 4) Quantitative analysis of each item to compare fairness with reconstruction. Therefore, this study is intended to understand problems of the remodeling system that is currently operated. Moreover, it will be further reviewed that the expansion of households is feasible through the permission of expansion and it will be discussed that the revitalization of the apartment remodeling has a positive impact on the residential environment.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1559-1563
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• 2009

Despite the serious lack of parking lots, studies on parking lot expansion are insufficient; research on users' satisfaction following parking lot expansion is practically nonexistent. Therefore, this study sought to provide basic data for the parking lot expansion of old apartments by comparatively analyzing users' satisfaction before and after the parking lot expansion through a questionnaire survey that targeted residents benefiting from the expanded parking lot. Results revealed a low post-occupancy satisfaction with the parking lot expansion despite the parking lot expansion and improvement of the parking lot environment. This was because the parking lot was not expanded up to the second basement floor due to the lack of appropriate parking space. Other factors included the construction cost burden and lack of connectivity of the basement parking lot with elevators. The results actually raise the need for the establishment of an optimally suitable expansion plan and development of method and technology requiring lower cost and shorter construction period in the design and construction processes for parking lot expansion. Through post-occupancy evaluation (POE) after parking lot expansion, this study quantitatively identified the problems associated with the parking lots of old apartments and ensuing expansion effects. The findings in this study can be used as basic data to seek a suitable diagnosis and evaluation method for the parking lots of old apartments.

• The korean journal of orthodontics
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• v.43 no.6
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• pp.302-310
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• 2013

Orthodontic closure of old, edentulous spaces in the mandibular posterior region is a major challenge. In this report, we describe a method of orthodontic closure of edentulous spaces in the mandibular posterior region accelerated by piezoelectric decortication and alveolar ridge expansion. Combined piezosurgical and orthodontic treatments were used to close 14- and 15-mm-wide spaces in the mandibular left and right posterior areas, respectively, of a female patient, aged 18 years and 9 months, diagnosed with skeletal Class III malocclusion, hypodontia, and polydiastemas. After the piezoelectric decortication, segmental and full-arch mechanics were applied in the orthodontic phase. Despite some extent of root resorption and anchorage loss, the edentulous spaces were closed, and adequate function and esthetics were regained without further restorative treatment. Alveolar ridge expansion-assisted orthodontic space closure seems to be an effective and relatively less-invasive treatment alternative for edentulous spaces in the mandibular posterior region.

• Communications of the Korean Mathematical Society
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• v.30 no.4
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• pp.481-491
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• 2015

We calculate volume ratio of a hypersurface orthogonal to a timelike geodesic relative to that of a hypersurface in the FLRW space-time.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.2
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• pp.46-51
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• 2002

Cold expansion of fastener holes is a mechanical process widely used in the aerospace industry. This treatment leads to an improvement of fatigue behavior due to the developed compressive residual stresses on the hole surface. The residual stress profile depends on the parameters of cold expansion, which are expanding rate, inserting direction of mandrel, material properties dtc. Despite its importance to aerospace industiries, little attention has been devoted to the accurate modeling of the process. In this paper, three-dimensional finite element simulations have been conducted for the cold expansion in an aluminium plate in order to predict the magnitude and distribution of the residual stress. To prove the results of FE analysis, the residual strain was measured by strain gage in cold expansion test. Maximum compressive residual stress could be increase about 7 percentage using the 2-step cold expansion method.

• Honam Mathematical Journal
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• v.9 no.1
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• pp.77-81
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• 1987

In this paper we introduce the notion of expansion mapping on a probabilistic metric space and prove common fixed point theorems for a pair of such mappings. These results being new of their kind. are interesting generafizations of some of the known results.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.108.2-108.2
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• 2011

We investigate decaying magnetohydrodynamic (MHD) turbulence by including the effects of expansion and collapse of the background medium. The problem has two time scales, the eddy turn-over time($t_{eddy}$) and the expansion/collapse time scale(${\tau}_H$). The turbulence is expected to behave differently in two regimes of $t_{eddy}$ < ${\tau}_H$ and $t_{eddy}$ > ${\tau}_H$. For instance, for $t_{eddy}$ < ${\tau}_H$, the turbulence would decay more or less as in a static medium. On the other hand, for $t_{eddy}$ > ${\tau}_H$, the effects of expansion and collapse would be dominant. We examine the properties of turbulence in the regimes of $t_{eddy}$ < ${\tau}_H$ and $t_{eddy}$ > ${\tau}_H$. Based on it, we derive a scaling for the time evolution of flow velocity and magnetic field.

• Proceedings of the Korean Statistical Society Conference
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• 2002.05a
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• pp.45-48
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• 2002

Consider the mean distance of Brownian motion on Riemannian manifolds. We obtain the first three terms of the asymptotic expansion of the mean distance by means of Stochastic Differential Equation(SDE) for Brownian motion on Riemannian manifold. This method proves to be much simpler for further expansion than the methods developed by Liao and Zheng(1995). Our expansion gives the same characterizations as the mean exit time from a small geodesic ball with regard to Euclidean space and the rank 1 symmetric spaces.