• Journal of Korean Society of Steel Construction
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• v.26 no.6
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• pp.537-547
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• 2014

A steel modular unit structural system has been used increasingly for mid and high-rise buildings, since the building can be easily constructed by assembling the pre-made modular unit structures. For this structural system, each modular unit structures have to be properly connected to the foundation to transfer the axial force and the bending moment that are generated from external load to the ground. In this study, a new type of the embedded steel column-to-foundation connection was proposed, and its flexural behavior was evaluated through a series of experimental study. Five full scale specimens for the proposed connections were constructed and tested. The effect of the main parameters that affect the flexural behavior of the proposed connection, such as embedment length and shape of end plate, were studied. From the results, it was found that the flexural stiffness of the proposed connection was higher than that of the semi-rigid connection for all test specimens, and 200 mm of embedment length was proper for the given test specimens in this study.

• Journal of Korean Society of Steel Construction
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• v.29 no.6
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• pp.435-442
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• 2017

A lateral load resisting system is a necessary structural element for the mid- to high-rise modular buildings and concrete cores are known as the most typical lateral load resisting systems in 10- to 20-story modular buildings. It is difficult to construct a concrete core simultaneously with the installation and finishing work of modular units because concrete placed using wet methods might contaminate or destroy the modular unit. Therefore, we have developed a hybrid PC (precast concrete) panel construction method that can construct a concrete core together with the installation of modular units. The hybrid PC panel is a load-bearing element in which a pair of C-shaped beams are combined at the top and bottom of a concrete wall. Concrete cores can be constructed by dry method to connect the hybrid PC panels with bolts. In this study, the details and connection of hybrid PC panels are improved to have the lateral performance comparable to reinforced concrete structural walls and are verified through FE analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.2840-2852
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• 2010

The number of North Korean refugees entering South Korea since the mid 1990s has increased continuously and recently the number has reached 2 million people, which is expected to continue to rise. In the meantime, the government of South Korea has been developing various means to help the North Korean refugees take part in our society and to increase their self-reliance. In this study, improvements were made to systems where North Korean national qualifications are made eligible for use in South Korea, to help them better adapt to our society. The research conducted a Delphi survey of 70 professional qualified workers, training specialists, qualified professionals, researchers and government agents, and 6 interviews were carried out to North Korean refugees and qualified judges. The results complement the current system, in terms of eligibility qualification procedures, where the department's role in its qualification procedure is enhanced and practical experiences are added to the procedure.

• The Journal of the Korea Contents Association
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• v.14 no.3
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• pp.125-139
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• 2014

In this study, we're going to look at the formation process of Youth film Festival and factors affecting that process. The Youth film Festival didn't appear suddenly in a day. There have been various trial regarding media education by civil society organizations (NGO) until the mid 1990s, principal Youth film Festival has been held from 1997s to 2001s and established a framework for Youth film Festival. There were some progress after those times and then in 2008 Youth film Festival faced some changes such as screening online, and responded rapidly to the current image industry and the cultural stream like the appearance of HD camcoder and smart phone till now. We can divide two areas regarding factors that affecting those formation process of Youth film Festival. First, they are explained as economic and social factors that the situation of South Korea extremely such as the efforts of civil society organizations (NGO), image technology and development of the industry, IMF bailout era and so on, second cultural and educational factors that the rise of virtual culture, the University entrance and results of awards. Thus Youth film Festival has been evolved in various affects, so we can look into the various sections of korea society through these formation process of Youth film Festival.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.2 s.48
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• pp.11-19
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• 2006

In this paper the seismic performances of 4, 10, and 30-story staggered truss systems (STS) were evaluated by observing the force-displacement relationship up io failure. The results were compared with the seismic performance of conventional moment resisting frames and braced frames. According to the analysis results, the STS showed relatively satisfactory lateral load resisting capability. However, in the mid- to high-rise STS, plastic hinges formed first at the chords were transferred to vertical members of the vierendeel panels, which formed a week link and subsequently leaded to brittle collapse of the structure. Therefore to enhance the ductility of STS it would be necessary to reinforce the vertical bracing members of the virendeel panels so that the plastic hinges, once toned in cord members of a virendeel panel, spread out to virendeel panels of neighboring stories.

• Earthquakes and Structures
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• v.18 no.3
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• pp.367-377
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• 2020

Incremental dynamic analysis (IDA) widely uses for the collapse risk assessment procedures of buildings. In this study, an IDA-based collapse risk assessment methodology is proposed, which employs a novel approach for detecting the near-collapse (NC) limit state. The proposed approach uses the modal pushover analysis results to calculate the maximum inter-story drift ratio of the structure. This value, which is used as the upper-bound limit in the IDA process, depends on the structural characteristics and global seismic responses of the structure. In this paper, steel midrise intermediate moment resisting frames (IMRFs) have selected as case studies, and their collapse risk parameters are evaluated by the suggested methodology. The composite action of a concrete floor slab and steel beams, and the interaction between the infill walls and the frames could change the collapse mechanism of the structure. In this study, the influences of the metal deck floor and autoclaved aerated concrete (AAC) masonry infill walls with uniform distribution are investigated on the seismic collapse risk of the IMRFs using the proposed methodology. The results demonstrate that the suggested modified IDA method can accurately discover the near-collapse limit state. Also, this method leads to much fewer steps and lower calculation costs rather than the current IDA method. Moreover, the results show that the concrete slab and the AAC infill walls can change the collapse parameters of the structure and should be considered in the analytical modeling and the collapse assessment process of the steel mid-rise intermediate moment resisting frames.

• 한국해양학회지
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• v.30 no.1
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• pp.13-26
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• 1995

In this paper three turbulence models including two-equation model by Blumberg and Mellor (1987), one-equation model with mixing length formula of Blackadar's (1962), and zero-equation model of Prandtl's (1925) were compared in homogeneous, unstratified channel flows. Steady flows which a steep-sided trapezoidal trench with uniform discharge, tidal flow and steady wind-driven flow in finite channels are considered in detail. Steady flows in a trench and tidal flows in a finite channel were reproduced fairly accurately and there was virtually no difference among results of three turbulence models. However, In case of steady wind-driven flow only two-equation model reproduced the important features of experimental data. the other two models underestimated the surface velocity. In tidal and wind-driven flows with negligibly small adjective and diffusive effects, the two-equation model gives rise to parabolic profile of eddy viscosity with maximum at the mid0depth, and the one and zero equation model based on Blackadar formula linear profile with maximum at the surface.

• Journal of Korean Society of Steel Construction
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• v.23 no.5
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• pp.595-606
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• 2011

This study was conducted to investigate the seismic behavior of steel member resisting frames considering the relative stiffness of the connection and beams. Six-story steel moment frames were designed to study the seismic behavior. The connections were classified into Double Web-Angle connections (DWAs), Top- and Seat-angles with double Web-angles (TWSs), FEMA-Test Summary No. 28, Specimen ID: UCSD-6 (SAC), and Fully Restrained (FR). The rotational stiffness of the semi-rigid connections was estimated using the Three-Parameter Power Model adopted by Chen and Kishi. The relative stiffness, which is the ratio of the rotational stiffness of the connections to the stiffness of the beams, was used. Push-over, repeated loading, and time history analysis were performed for all the frames. The seismic behavior of each frame was analyzed with the story drift, plastic hinge rotation, and hysteretic energy distribution.

• Korean Journal of Community Nutrition
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• v.11 no.3
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• pp.361-373
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• 2006

The purpose of this study was to identify the difference of school food service dietitians' work value, job satisfaction, and turnover intention based on their expectation to be a nutrition teacher. Also, this study explored the differences in expectation to be a nutrition teacher, work value, job satisfaction, turnover intention depending on demographics and school foodservice operational characteristics. This study surveyed dietitians who worked at school foodservice in Kyunggii and Daegu Gyeoungbuk Province. A total of 509 responses were collected using on-site survey and online survey (59.3%). Dietitians expressed favorable work value ($3.88{\pm}0.34$) and mid level of a job satisfaction ($2.99{\pm}0.64$). The percentage of dietitians who had an intention to leave after the promulgation of a nutrition teacher system (13.2%) was lower than that of dietitians who had an intention to leave prior to it (23.2%). Most dietitians expected a salary rise (84.7%), more chance to teach nutrition education (76.0%), and the improvement of power not only as a teacher but as a dietitian (72.7%). Dietitians who had higher expectation levels to be a nutrition teacher (> 3 on the 5 point Likert scale) showed a higher tendency of significant turnover intention (F = 4.40, p < 0.01) and more confident work value (F = 15.292, p < 0.001) when comparing those who had lower expectations. There were significant differences in work value, job satisfaction, turnover intention, and expectation to be a nutrition teacher depending on career length and employment status of dietitians. This study revealed that school food service dietitians have favorable expectations to be nutrition teachers with high work value.

• Applied Microscopy
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• v.33 no.4
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• pp.325-333
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• 2003

Fine structural characteristics of the heart tube and its cardiac muscle cells in spider, Araneus ventricosus are investigated by both of scanning and transmission electron microscopes. The heart tube of the spider is extended mid-dorsally along the anterior part of the abdomen, and is consisted of the thin outer layer of connective tissue (epicardium) and the thick muscle layer (myocardium). The myocardium in the spider has a typical fanlike spiral structure toward anterior part put across between the muscle fibers. Therefore, it did not give rise to the intima, and muscle cells are in direct contact to the hemolymph. The heart tube appeared to be three pairs of ostia and numerous hemocytes accumulated at the inner surface of the myocardial layer. Among several kinds of the hemocytes, the oenocytoids are the most predominant hemocytes accumulated along the myocardial folds which stretched toward heart lumen. The heart muscle cells are cross striated, branched, and multinucleated. They contain a lot of mitochondria, which provide for the continuous energy demands of the heart. Thread-like ganglion on the dorsal side of the heart tube gives off axons that innervate the heart muscle cells.