• Journal of the Korean Society of Safety
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• v.30 no.2
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• pp.41-47
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• 2015

Recently, a lot more disasters in the temporary structures happen because the stabilities of the temporary structures are disregarded by the reduction of the unit cost, using defective materials, the existing materials and so on. Pipe supports, which are one of the temporary structures, are basically used for the most constructing works such as buildings, bridges, plants and so on. In the most sites, adequate support installations of the pipe supports have not been performed although the presence of the guideline legally and institutionally. In this study, therefore, the collapse accidents of the pipe supports were investigated on the basis of theoretical analysis as well as the buckling tests by simulating the site support condition. Both the theocratical analysis and test results show that the buckling load in the fixed ends is at least 4 times larger than one in the pinned ends. This results will be utilized for safety assurance as well as accident prevention the in the field application.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.2_2
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• pp.245-254
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• 2020

This study investigated the so far little-researched characteristics of the behaviors of rock slopes at the time of an earthquake. For the selection of the rock block, a proper model was formed by applying the similarity in consideration of the roughness and strength of the rock slope(10m) on the site, and shaking table tests were carried out according to seismic excitement acceleration, and seismic waves. In the case of the inclination angle of the joint plane of 20°, the long period wave at 0.3g or more at the time of the seismic excitement surpassed the length of 100mm, the permissible displacement (0.01H, H:slope height), which brought about the collapse of the rock; the short period wave surpassed the permissible displacement at 0.1g, which caused the collapse of the slope. The rock slope was close to a rigid block and a structure more vulnerable to the long period wave than to the short period wave. It collapsed in the short period wave even at the seismic amplitude smaller than the maximum design acceleration in Korea.

• The Research Journal of the Costume Culture
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• v.18 no.6
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• pp.1261-1273
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• 2010

The advent of various arts and remarkable development of mass media since 1980s accelerate fashion photographs' advancement. The expression of fashion through photographs can represent characteristics of ages, societies, cultures, traits of designers and techniques of photographers. In addition, that is the tool which contains economical role as a product and artistic role as photos. Therefore, this study examines hyprt-reality images in editorial fashion photographs. Hyper-reality means the reproduction which represents the reality of life more actually. Hyper-reality through photographs elevates reality of virtual things and creates the confused situation which haunts the boundary between reality and reproduction. This study classifies the hyper-reality in editorial fashion photographs into three groups by their external traits, ideal reality, collapse of reality, and restoration of reality. First, ideal reality is represented as harmony among fashion, characters, and space, causality of fashion with time and circumstances, positive will, and melting with nature. Second, collapse of reality is expressed as in harmony between fashion and situation, violence, fetishism and symbol of death. Third, restoration of reality is shown as recurrence to nature and images of utopia to express dignity of life.

• Earthquakes and Structures
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• v.18 no.1
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• pp.57-72
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• 2020

This paper presents the results of a monodirectional shaking table test on a full-scale unreinforced masonry cross vault characterized by asymmetric boundary conditions. The specimen represents a vault of the mosque of Dey in Algiers (Algeria), reproducing in detail the mechanical characteristics of masonry, and the constructive details including the presence of some peculiar wooden logs placed within the vault's abutments. The vault was tested with and without the presence of two steel bars which connect two opposite sides of the vault. The dynamic behaviour of both the vault's configurations were studied by using an incremental dynamic analysis up to the collapse of the vault without the steel bars. The use of an innovative high-resolution 3D optical system allowed measure displacement data of the cross vault during the shake table tests. The experimental results were analysed in terms of evolution of damage mechanisms, and in-plane and out-of-plane deformations. Moreover, the dynamic properties of the structure were investigated by means of an experimental modal analysis.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.3
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• pp.37-43
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• 2006

Six types of hat stiffened composite panels were manufactured with different bonding methods and stiffener section shapes and compression testing of these panels were performed. The panels showed similar behaviors in bucking and postbuckling region before a skin-stiffener separation failure occurred. Although all the separation failures occurred at the same locations of stiffener flanges close by skin buckling crests, the separation loads, separation failure growth behaviors and final collapse loads were different with respect to bonding methods and stiffener section shapes. As the separation failure initiated early and propagated larger area, collapse loads and structural efficiency of the panels decreased.

• Journal of the Korean GEO-environmental Society
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• v.13 no.3
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• pp.13-19
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• 2012

Due to recent climate change, big typhoon and heavy rainfall happen frequently not only in Korea but also all over the world. It leads to collapse of levee by extraordinary flood. It lead to collapse of levees by extraordinary flood. These natural disasters give the life and property damages in near region. In this study, it was performed that a stability in levee using seepage analysis. It has been evaluated hydraulic gradient of exit zone according to variations in levee crest width, gradient. As a result, it showed that hydraulic gradient of exit zone was decreased due to increase of levee crest width and gradient, and it was evaluated that vertical hydraulic gradient was decreased than that of the horizontal hydraulic gradient.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.1
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• pp.56-63
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• 2007

In case of bus rollover, the body structure of the bus should be designed to ensure the survival space for passengers. So, this study focuses on evaluating rollover strength through a computer simulation using the commercial code, LS-DYNA3D at the initial stage of vehicle development. For this study, section structure was modeled using a simple beam element, and impact boundary conditions required by ECE(Economic Commission for Europe) regulation No.66 were applied. In order to confirm the validity of the beam element bus model, the results compared with the test results and shell element bus model. The analysis errors from beam element bus model are due to the difference in strain energy of joint area between beam and shell model. In this study, a method for the joint modeling was suggested by using nonlinear springs to which the collapse mechanisms were applied.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.3-5
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• 1994

It is shown that the power flow considering the voltage characteristic of the composite load has some difference comparing with conventional load flow in this paper. When the load flow is used in a study of the static voltage stability, it is necessary to consider the voltage characteristic of load, since the composite load of a typical power system bas constant power, constant current, and constant impedance characteristic. The load is modeled to a polynomial form in here, and used in solving the load flow problem. In this way, the effect which the voltage characteristic of the load has on several voltage collapse proximity indicator based on sensitivities is compared with the conventional load flow, or with another load model having a different voltage characteristic. In this paper, the voltage collapse proximity indicator using the sensitivity of real power for transmission loss is also proposed, and compared with other indicators.

• Geomechanics and Engineering
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• v.13 no.3
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• pp.505-515
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• 2017

Based on the collapse characteristics of a shallow rectangular cavity, a three-dimensional failure mechanism which can be used to study the collapsing region of the rock mass above a shallow cavity roof is constructed. Considering the effects of surcharge pressure and surface bolt on the collapsing block, the external rate of works produced by surcharge pressure and surface bolt are included in the energy dissipation calculation. Using variational approach, an analytic expression of surface equation for the collapsing block, which can be used to study the collapsing region of the rock mass above a shallow cavity roof, is derived in the framework of upper bound theorem. Based on the analytic expression of surface equation, the shape of the collapsing block for shallow cavity is drawn. Moreover, the changing law of the collapsing region for different parameters indicates that the collapsing region of rock mass decreases with the increase of the density of surface bolt. This conclusion can provide reference for practicing geotechnical engineers to achieve an optimal design of supporting structure for a shallow cavity.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.80.1-80.1
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• 2021

Intensive Monitoring Survey of Nearby Galaxies (IMSNG) is a program monitoring nearby galaxies with a high cadence within a day. The main goal of the project is to constrain the SNe explosion mechanism and properties of their progenitors by catching the early lights from the shock-heated cooling emission. The observation campaign began in 2014 with two 1-m class telescopes in the northern hemisphere. Now more than ten telescopes are monitoring galaxies with 60 IMSNG targets, which have a high probability of supernova explosion every night all around the world. Since the project started, the following observations have been carried out on 14 SNe Ia(including -pec), 27 core-collapse supernovae (CCSNe), and around 40 transients in other types. In this poster, we present the current status of IMSNG SNe data first and then focus more on the CCSNe. CCSNe are the explosion of massive stars, more massive than eight times of the Sun. They have been studied for more than a half decades but still have key questions to be solved, such as distinct types, the characteristics driving their diversity, and so on. Here, we show our ongoing studies of CCSNe in IMSNG, focusing on their usefulness as distance indicators and properties of early light curves.