• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.327-329
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• 2012

The validity of the numerical model used in the program is established by comparing the prediction from the computer program with results from full-scale fire resistance tests. Details of fire resistance experiments carried out on reinforced concrete slab, together with results, are presented. The results obtained from experimental test indicated in that the proposed numerical model and the implemented codes are accurate and reliable.

• Journal of the Korean Institute of Educational Facilities
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• v.9 no.4
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• pp.95-102
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• 2002

The purpose of this study is to renovate a closed school to a artist studio complex applying sustainable principles and methods. Through the case study, the principle and methods of sustainable renovation is investigated and following strategies are extracted as a frame of renovation. First, atrium space with thermal mass using existing wall is proposed as a public gathering space. Second, light shelves for effective lighting and shading device for protecting and allowing sun light is proposed to renovate existing classroom. Third, double skin system is proposed with reflection pool to activate heating and ventilation for passive solar as well as passive cooling. Finally, simulation programs such as energy-10 and Form-Z is used to confirm the validity of the sustainable design.

• International Journal of Aeronautical and Space Sciences
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• v.2 no.1
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• pp.1-11
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• 2001

The time implicit point SGS scheme is applied to compute hypersonic viscous flows in thermochemical nonequilibrium. The performance of the point SGS scheme is then compared with those of the line SGS and the LU-SGS schemes. Comparison of convergence histories with the effect of multiple forward and backward sweeps are made for the flow over a 2D cylinder experimentally studied by Hornung and the flow over a hemisphere at conditions corresponding to the peak heating condition during the reentry flight of an SSTO vehicle. Results indicate that the point SGS scheme with multiple sweeps is as robust and efficient as the line SGS scheme. For the point SGS and the LU-SGS scheme, the rate of improvement in convergence is largest with two sweep cycles. However, for the line SGS scheme, it is found that more than one sweep cycle deteriorates the convergence rate.

• Journal of Astronomy and Space Sciences
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• v.3 no.2
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• pp.117-122
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• 1986

The broadband electrostatic noise has been observed in the boundary layer region of the earth's magnetosphers. These electrostatic waves believed to be generated by drifting ion beams in the matnetotail. We have shown the numerical simulation result of ion beam acoustic instability in the magnetotail. This instability heats both background and beam ion in the boundary layer of neutral sheet observed by satellite.

• Journal of The Korean Astronomical Society
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• v.34 no.4
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• pp.247-249
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• 2001

The accretion disks are usually supposed symmetric to reflection on the Z=0 plane. Asymmetries in the flow are be ver-y small in the vicinity of the compact accretor. However their existence can have a important role in the case of subkeplerian accretion flows onto black holes. These flows lead to strong heating and even to the formation of shocks close to the centrifugal barrier. Large asymmetries are due to the development of the KH instability triggered by the small turbulences at the layer separating the incoming flow from the out coming shocked flow. The consequence of this phenomenon is the production of asymmetric outflows of matter and quasi periodic oscillations of the inner disk regions up and down the Z=0 plane.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.56.1-56.1
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• 2011

We investigate the hydrodynamics of gas clouds in the central few hundred parsecs of the Galaxy. Non-axisymmetry (elongation) of the Galactic bulge can form a reservoir of dense molecular clouds at around two hundred parsecs from the center through the X1-X2 orbit transfer, and the star formation that has been sustained for the lifetime of the galaxy can build up a nuclear bulge there. If the nuclear bulge is elongated, this again can transport the gas there down to the central few parsecs region. We perform a series of 3-D hydrodynamic simulations that consider a potential for this "nested bar", cooling/heating, star formation and supernova feedback, and estimate the efficiency of the gas inflow down to the central parsec region.

• Journal of The Korean Digital Architecture Interior Association
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• v.7 no.1
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• pp.29-34
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• 2007

Purpose of this paper is find the similarity and dissimilarity of Korean, Chinese and Japanese traditional furnitures for storage. Also this paper tries to have a comparative analysis on life style, characteristics of housing space and furniture's form of three countries. The study can be summarized as follows. First, space scale and seat levels of three countries are related to furniture's height and form, so that Chinese furniture have over scale than human, and Japanese furniture have the type of box for stacking. Second, the way of heating and materials of floors are concerned with the type of furniture's legs. Third, even if these dissimilarities, the aesthetic characteristics of three countries furniture would be a data base for making design identity of East Asian modern housing furniture.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.76-81
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• 2007

The shopping center in underground passage increased for efficient space utilization in urban area. This study describes operation characteristics of all air type and hybrid type with local ventilation and fan coil unit fixed to ceiling. In order to compare energy saving, thermal environment and installation space, etc., integrated simulator with heat production and indoor distribution system is designed and constructed. Energy saving of the hybrid system is calculated as over 30% compared to conventional all air type. And also the results showed that humidity decreased about 6%, also indoor thermal distribution is improved as temperature variation of around $1^{\circ}C$.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.593-596
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• 2006

This paper introduces various natural energy systems installed at the Eco-Science Center in Geumsan near Taejon. The center, especially, features different solar energy systems to harvest the solar energy to its full extent. Such passive schemes as direct gain and at lacked sun space are applied along with active solar ingredients using flat plate and double skin solar collectors. Space and water heating depends very little on the conventional means. Also a number of photovoltaic modules deployed within its premise supplies power to drive a water pump for the biotop. Combined with other natural energy utilizing systems, the solar energy systems make an exemplary model of a self sustainable public facility which is the first of its kind in Korea.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.47.1-47.1
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• 2021

Transverse magnetohydrodynamic waves often called Alfvénic (or kink) waves have been often theoretically put forward to solve the outstanding problems of the solar corona like coronal heating, solar wind acceleration, and chemical abundance enhancement. Here we report the first spectroscopic detection of Alfvénic waves around a sunspot at chromospheric heights. By analyzing the spectra of the Hα line and Ca II 854.2 nm line, we determined line-of-sight velocity and temperature as functions of position and time. As a result, we identified transverse magnetohydrodynamic waves pervading the superpenumbral fibrils. These waves are characterized by the periods of 2.5 to 4.5 minutes, and the propagation direction parallel to the fibrils, the supersonic propagation speeds of 45 to 145 km s-1, and the close association with umbral oscillations and running penumbral waves in sunspots. Our results support the notion that the chromosphere around sunspots abounds with Alfvénic waves excited by the mode conversion of the upward-propagating slow magnetoacoustic waves.