• Korean Institute of Interior Design Journal
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• v.17 no.6
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• pp.178-187
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• 2008

This study aims to analyze general features and forms of spatial structure of major space in museums and for the scope of this study, set up major space and the surrounding areas structured around major space and for the target of analysis, selected 10 museums of overseas examples from 19th century to 2006. And this study on focus, on the circulation structure and visual structure will be analyzed in qualitative method by focusing on the floor plan and section structures; deepening process of analysis, visual structure will turn into numerical value to analyze the spatial structure of the major space. The results of this study are as follow. First, vertical elements should be critically considered in a circulation plan for functional performance of dimensional circulation distribution in a major space. Second, a plan by location of vertical and horizontal moving elements related to a major space affects a circulation relation more than a connection type between a major space and an exhibition area. Third, it could be categorized into 4 types by considering the features of spatial structure followed by connecting relationship between areas. Fourth, comparable figures were drawn out among large space and surrounding areas but it couldn't draw out types.

• Journal of Korean Association for Spatial Structures
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• v.23 no.4
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• pp.27-34
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• 2023

In this study, the seismic response characteristics of the three analysis model with or without TMD were investigated to find out the effective dome shape. The three analysis models are rib type, lattice type and geodesic type dome structure composed of space frame. The maximum vertical and horizontal displacements were evaluated at 1/4 point of the span by applying the resonance harmonic load and historical earthquake loads (El Centro, Kobe, Northridge earthquakes). The study of the effective TMD installation position for the dome structure shows that seismic response control was effective when eight TMDs were installed in all types of analysis model. The investigation of the efficiency of TMD according to dome shape presents that lattice dome and geodesic dome show excellent control performance, while rib dome shows different control performance depending on the historical seismic loads. Therefore, lattice and geodesic types are desirable for seismic response reduction using TMD compared to rib type.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.2
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• pp.175-188
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• 2009

When a new tunnel is excavated by the drill and blast method near pre-existing underground structures or tunnels due to the region restricted condition such as urban area, the ground will be relaxed by the excavation. In this case, issues can be created in terms of stability of pre-existing underground structures. One of major factors determining the stability of pre-existing underground structures can be a separation distance between pre-existing underground structures and a newly excavated tunnel. The region of ground relaxation defined by the plastic zone due to new excavation can be varied by separation distance. In this study, in other to estimate an influence of new tunnel excavation in terms of separation distance on the stability of pre-existing large pipelines, two-dimensional scaled model tests using plaster were performed for six models which have a different separation distance, The results show that based on the analysis of induced displacement during tunnel construction, the displacement decreases as the separation distance between large pipeline and new tunnel is increased until the distance is 2.5 times of pipeline diameter. Beyond this point, however, the displacement has become stabilized.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.94.2-94.2
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• 2011

Electron microbursts, energetic electron precipitation having duration less than 1 sec, have been thought to be generated by chorus wave and electron interactions. While the coincidence of chorus and microburst occurrence supports the wave-particle interaction theory, more crucial evidences have not been observed to explain the origin of microbursts. We propose the measurement of energy dispersion of microbursts could be an evidence supporting wave-particle theory. During chorus waves propagate along magnetic field, the resonance condition should be satisfied at different magnetic latitude for different energy electrons. If we observed electron microbursts at low altitude, the arrival time of different energy electrons should make unique dispersion structures. In order to observe such energy dispersion, we need a detector having fast time resolution and wide energy range. Our study is motivated from defining the time resolution and energy range of the detectors required to measure microburst energy dispersions. We performed test particles simulation to investigate how electrons interact with simple coherent waves like chorus waves. We compute a large number of electron's trajectories and successfully produce energy dispersion structures expected when microbursts are observed with 10 msec time resolution detectors at the altitude of 600 km. These results provide useful information in designing electron detectors for the future mission.

• Journal of Ocean Engineering and Technology
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• v.13 no.4 s.35
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• pp.19-27
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• 1999

To design a very large floating structure, such as a floating airport, we have to estimate the hydroelastic responses of a very large floating structure (VLFS) exactly. We developed the numerical method for estimating the hydroelastic responses of the VLFS. The developed numerical approach is based on a combination of the three-dimensional source distribution method, the wave interaction theory and the finite element method for structurally treating the space frame elements. The Numerical results of the hydroelastic responses and steady drift forces of a somisubmersible type offshore structure, which is supported by the 33(3 by 11) floating bodies, with various bending rigidities are illustrated.

• The Journal of the Acoustical Society of Korea
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• v.38 no.1
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• pp.67-72
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• 2019

In this study, we investigate the echo reduction performance of miniaturinzed Helmholtz resonators using smaller than wavelength acoustic metamaterial structures. The Helmholtz resonators are formed using air structures which exhibit large impedance mismatch with the surrounding underwater environment. Using the multi-physics software package, we find that significant reduction in the sonar signature is expected and frequency tailoring is possible by controlling the degree of space coiling and inner volume of the resonators. We find that for the basic Helmholtz resonators, up to 7 dB reduction in echo is expected at 10,000 Hz while when the miniaturized Helmoholtz resonators are used, up to 14 dB reduction in echo is expected at 5,000 Hz. In addition, frequency tailoring is demonstrated by varying the internal volume of the Helmholtz resonators and broadband characteristic is shown using superposition of various degree of space coiled structures. Through this study we investigate the effectiveness of the miniaturized Helmholtz resonators formed using air structures and the echo reduction results show promisses in the application of achieving underwater stealth.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.4
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• pp.150-161
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• 1996

A numerical procedure is described for predicting steady drift forces on very large offshore structures supported by a large number of the floating bodies of arbitrary shape dimensional source distributing method, the wave interaction theory, the far-field method of using momentum theory and the finite element method for structurally treating the space frame elements. Numerical results are compared with the experimental or numerical ones, which are obtained in the literature, of steady drift forces on a offshore structure supported by the 33(3 by 11) floating composite vertical cylinders in waves. The results of comparison confirmed the validity of the proposed approach.

• Wind and Structures
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• v.26 no.1
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• pp.11-24
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• 2018

Full-scale measurements of wind action on the open roof structure of the WuXi grand theater, which is composed of eight large-span free-form leaf-shaped space trusses with the largest span of 76.79 m, were conducted during the passage of Typhoons HaiKui and SuLi. The wind pressure field data were continuously and simultaneously monitored using a wind pressure monitoring system installed on the roof structure during the typhoons. A detailed analysis of the field data was performed to investigate the characteristics of the fluctuating wind pressure on the open roof, such as the wind pressure spectrum, spatial correlation coefficients, peak wind pressures and non-Gaussian wind pressure characteristics, under typhoon conditions. Three classical methods were used to calculate the peak factors of the wind pressure on the open roof, and the suggested design method and peak factors were given. The non-Gaussianity of the wind pressure was discussed in terms of the third and fourth statistical moments of the measured wind pressure, and the corresponding indication of the non-Gaussianity on the open roof was proposed. The result shows that there were large pulses in the time-histories of the measured wind pressure on Roof A2 in the field. The spatial correlation of the wind pressures on roof A2 between the upper surface and lower surface is very weak. When the skewness is larger than 0.3 and the kurtosis is larger than 3.7, the wind pressure time series on roof A2 can be taken as a non-Gaussian distribution, and the other series can be taken as a Gaussian distribution.

• Journal of Navigation and Port Research
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• v.27 no.1
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• pp.63-70
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• 2003

If semi-rigid connections are used for superstructures of very large floating structures (VLFS), the number of rigid connections can be reduced and more economical construction will be possible. In this study, considering service load and wave load in VLFS, the applicability of mixed use of rigid and semi-rigid connections have been studied using three types of connections for a four-bay eight-story frame. Three types of connections are used; top and seat-angle connections with double web-angle(TSD), extended end plate connections, steel tubular column with square external-diaphragm connections. ABAQUS(Finite element analysis program) is used for conducting second order elastic analysis.

• Journal of Korean Association for Spatial Structures
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• v.20 no.3
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• pp.35-42
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• 2020

The purpose of this study is to develop precast concrete modules that can be used as a booth and a single-story building with a large space. This precast concrete module is originally designed to have a hexagonal facade when the upper and lower parts, which are symmetrical about horizontal connection line, are combined. A structural design was conducted to ensure structural safety of these precast concrete modules and to extend the slope of the inclined members as far as possible. Then the finite element analysis was performed to estimate the lateral and vertical deflection of complete precast concrete modular structures. And to verify the structural safety of these precast concrete modules, weight loading tests were conducted on the upper and lower modules respectively.