• Journal of Korean Society of Steel Construction
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• v.23 no.1
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• pp.41-49
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• 2011

A long-span (more than 8m) plastic greenhouse is currently being used in farms due to its magnified benefits, such as the convenience of the farming equipment used, and the land usage efficiency. In this study, the reinforcing effects of the use of a pretension tie were shown. In a previous study, tests for a 6.5m single-span-type greenhouse announced by Rural Development Administration were carried out. The tests of symmetric and eccentrics now loading by the sun and wind were conducted for the 10.2m span with a ${\phi}48.1{\times}2.1$ section in this study, after which the load-deflection relationship was compared for the cases of reinforcement with a tie and without a tie. The results of the symmetric snow loading test showed that the strength increased by 68~93% in the case of the specimen with a tied arch. The failure mode of the specimen without a tie tended to be that with a sway failure mechanism, and that of the reinforcement specimens with a tie tended to be that with an arch buckling mechanism. The results of the eccentric snow loading test showed that the strength of the specimen with a tie increased by 10~20% compared to that of the specimen without a tie. For the failure mode of the latter, a combined failure mechanism was adapted, although the failure mode of the tied specimens tended to be that with an arch buckling mechanism.

• Journal of the Korea Concrete Institute
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• v.15 no.2
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• pp.225-233
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• 2003

Even though a lot of advanced researches on analysis, design, and performance evaluation of reinforced concrete (RC) under seismic action have been carried out, there has been only a few study on seismic analysis of underground RC structures surrounding soil medium. Since the underground RC structures interact with surrounding soil medium, a path-dependent soil model which can predict the soil response is necessary for analyzing behavior of the structure inside soil medium. The behavior of interfacial zone between the RC structure and the surrounding medium should be also considered for more accurate seismic analysis of the RC structure. In this paper, an averaged constitutive model of concrete and reinforcing bars for RC structure and path-dependent Ohsaki's model for soil are applied, and an elasto-plastic interface model having thickness is proposed for seismic analysis of underground RC structures. A finite element analysis technique is developed by applying aforementioned constitutive equations and is verified by predicting both static and dynamic behaviors of RC structures. Then, failure mechanisms of underground RC structure under seismic action are numerically derived through seismic analysis of underground RC station structure under different seismic forces. Finally, the changes of failure mode and the damage level of the structures are also analytically derived for different design cases of underground RC structures.

• Korean journal of communication and information
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• v.48
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• pp.63-89
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• 2009

The contents provided by the terrestrial broadcasters have governed the market based on their excellent quality in Korea. In spite of the launching of various pay TV services focusing on multi-channel, it is not yet easy to find out the substitutionary pay TV channels for the terrestrial. Therefore, the real time retransmission of the terrestrial channels brings about the crucial effects on the pay TV's competency, especially on the new media as the invisible barrier. So it is frequently proposed to change the aim of the retransmission policy from the universal access to the promotion of media industries. The retransmission can be divided into two types as the must carry and retransmission consent. In Korean situation, keeping or reducing the must carry channel would be appropriate rather than expanding them. However, periodic investigation into the public effects of the must carry is necessary, instead of it. Moreover, the rational and fair monetary compensation for the commercial channels(MBC, SBS, KBS2) is arising as the bottle neck in the retransmission agreements between the broadcasters. The conjoint analysis was carried out to estimate the welfare growth from the retransmission, based on the stated preference from the audiences' point of view. For must carry channels, it was certified as the 'win-win' strategy for both sides and audiences. For the commercial channels, it is revealed to be beneficial to the audiences. Thereafter, the standards for the rational price were suggested to promote the retransmission. This can contribute for inspiring the dynamic vitality to the media industry by reinforcing the contents competencies and for establishing the long term growth strategies.

• Journal of the Korea Concrete Institute
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• v.27 no.6
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• pp.615-623
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• 2015

The previous strut-and-tie models (STMs) to evaluate the shear strength of squat shear walls with aspect ratio less than 2.0 do not consider the axial load transfer of concrete strut and individual shear transfer contribution of horizontal and vertical shear reinforcing bars in the web. To overcome the limitation of the existing models, a simple STM was established based on the crack band theory of concrete fracture mechanics. The equivalent effective width of concrete strut having a stress relief strip was determined from the neutral axis depth and effective factor of concrete strength. The shear transfer mechanism of shear reinforcement at the extended crack band zone was calculated from an internally statically indeterminate truss system. The shear transfer capacity of concrete strut and shear reinforcement was then driven using the energy equilibrium in the stress relief strip and crack band zone. The shear strength predictions of squat shear walls evaluated from the current models are in better agreement with 150 test results than those determined from STMs proposed by Siao and Hwang et al. Furthermore, the proposed STM gives consistent agreement with the observed trend of the shear strength of shear walls against different parameters.

• Journal of the Korea Concrete Institute
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• v.20 no.6
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• pp.697-704
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• 2008

This paper presents an analytical prediction of Nonlinear characteristics of prestressed concrete bridges by strengthened of externally tendon considering construction sequence, using unbonded tendon element and beam-column element based on flexibility method. Unbonded tendon model can represent unbounded tendon behavior in concrete of PSC structures and it can deal with the prestressing transfer of posttensioned structures and calculate prestressed concrete structures more efficiently. This tendon model made up the several nodes and segment, therefore a real tendon of same geometry in the prestressed concrete structure can be simulated the one element. The beam-column element was developed with reinforced concrete material nonlinearities which are based on the smeared crack concept. The fiber hysteresis rule of beam-column element is derived from the uniaxial constitutive relations of concrete and reinforcing steel fibers. The formulation of beam-column element is based on flexibility. Beam-column element and unbonded tendon element were be involved in A computer program, named RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), that were used the analysis of RC and PSC structures. The proposed numerical method for prestressed concrete structures by strengthened of externally tendon is verified by comparison with reliable experimental results.

• Journal of forensic and investigative science
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• v.2 no.1
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• pp.23-31
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• 2007

Apartments are built in small countries to accommodate densely populated cities and maximize urbanization. Many apartment complexes have been built in recent reconstruction or redevelopment projects. An increase in crime has resulted due to residents living in a narrow space. Larceny is the most commonly reported crime in apartment complexes. Apartments can be classified as stairway, hallway, or plane surface. This study compares and analyzes the frequency of theft by apartment type to assist in creating a safer residential space. In America and England, scholars studied to make a safer residential space, and have applied the theory of 'the Defensible Space' and 'Crime Prevention Through Environmental Design(CPTED)' since 1970s. Korean apartment design now reflects CPTED in new apartment construction. In this study, 12 apartment complexes were selected in Changwon city to conduct analysis of theft in selected complexes. The study will cover housing invasion theft, motorcycle and car theft and snatching. The most frequency larceny is motorcycle and car theft, the second is housing invasion theft, and the least frequent is snatching. More residents' motorcycles and cars are damaged in a hallway style apartment. More frequently inhabitants have their possessions snatched on a stairway form. 1) When we build new apartment complexes, we must plan to improve territoriality and enhance a natural surveillance by reinforcing dwellers' relationship. Through planning we can prevention the larceny in apartments.

• Journal of Korean Home Economics Education Association
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• v.25 no.1
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• pp.119-135
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• 2013

This Exploratory study applied the content analysis method by documental research to develop the logic of announcing a validity of Korean Education or Home Economics Education's roles and missions for preventing the school violence. As the results, three logics of accessing devices for Korean Education or Home Economics Education got developed. First, adolescents should be changed into an positive perspective like a 'people living' rather than a negative perspective like the 'learner' which is limited in Korean Education. Second, the value of the 'life competency' which has been disparaging is reinforced as an important value of education although the purpose of Korean Education was only one. The life competency is not a talent which is learned naturally by experiences. Because the school violence which is a problem in nowadays is a problem occurred by adolescents as the 'people living' rather than the 'learner', it is needed to renovate an education by a curriculum of reinforcing the 'life competency'. Third, Home Economics Education has been traditionally the typical subject which had a purpose of varied competency development as the 'people living'. Thus, the subject of Home Economics Education is one of the most important subjects, being able to prevent the school violence in entire Korean Education. The Home Economics Education as the 'life education' has an essence for making adolescents have needed competency to achieve a qualified and happy life over their adjustment.

• Korean Journal of Health Education and Promotion
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• v.16 no.2
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• pp.19-40
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• 1999

In order to ascertain the attitudes of residents to their health and the National Health Promotion Law, surveyors interviewed 1,220 subjects, 1% of men and women in Kyungsan city, who were twenty-year-old or more. The major findings are as follows: Men and women were 48.2% and 51.8%, respectively. The recognition rate of enacting and enforcing this law is 59.2% of men and 51.3% of women. With regard to the behavioral attitude to the health in the distinction of sex and age, current smokers are 31.2% of the interviewees, 61.6% of the men and 3.3% of the women. Current drinkers are 35.1%, 59.5% of the men and 12.3% of the women, but on the other hand there is little significance in the distinction of age. The acknowledgement proportion of enacting and enforcing this law is 59.2% of male and 51.3% of female. In terms of the recognition rate of the contents according to the general characteristics of interviewees, it appears that the indication of a warning expression on a packing paper of cigarette case and a liquor bottle is 92.4% and also the designation of a smoking free area in public facilities is 94.8%. Prohibition of cigarette-sale to the teenagers who are under 19, is 96.0%. Considering these facts, the recognition rate is high. On the contrary, 48.8% is accounted for encouraging a medical check-up before marriage which is in a low position. As a result of multiple behavior as a independent educational level, marital significant variables. In case of having undergone a periodic medical examination the recognition rate was high whereas frequent exercise led to the low recognition rate. Concerning the details of the undertaking in accordance with each factor of general characteristics, the greater part of them have been appraised successfully whether it is recognized or not. On the other side, no effect got answered about the result of the undertaking subjects to general and peculiar behavior attitude towards health was in effect or not. A great majority approved of more reinforcement of legal regulation about smoking and drinking regardless of whether they perceived the details of the law of promotion of National Health Promotion Law or not. Additionally there was significant difference in reinforcing legal regulation of smoking and drinking in compliance with the attitude of the substance of this law. With regard to education, public relations and evaluation about national health through public health centers by our government, the younger and the higher in education they are, the more deficient they feel. First of all, those who were aware of the enforcement of this law as well as plenty of scarcity answered that better service of disease prevention had to be expanded than ever. In consideration of the above-stated results, the education to public health and the business of public relations should be reinforced and a practical campaign for health life should also spread out for the purpose of encouraging to practise healthy life-style.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.4
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• pp.397-403
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• 2012

The vitality of immature tooth could be lost by dental caries, trauma and fracture of malformed tooth. The vitality loss might lead to halt of the development of the root. The recommended endodontic treatment for a non-vital immature permanent tooth is apexification. Apexification is a method of inducing apical closure through the formation of mineralized tissue in the apical pulp region. Calcium hydroxide is the material of choice for apexification. Long-term exposure to calcium hydroxide may form the apical hard tissue, but weaken the dentin due to its alkaline nature and thus make the roots more susceptible to fracture. It is important to preserve any weakened tooth, so a permanent restoration is needed to reinforce teeth that are prone to fracture. The purpose of this case report was to describe the treatment for reinforcing immature teeth treated with long-term calcium hydroxide. In these cases, the apexes of teeth were sealed with MTA plugs and the root canals were restored with composite resin and fiber post.

• Journal of The Korean Association For Science Education
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• v.31 no.4
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• pp.609-620
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• 2011

This study examined how pre-service science teachers, who observed classes for the gifted in science, perceive the gifted in science and the education they are getting, and explored what needs to be improved in the classes for the gifted in science. Based on the results of this study, first, pre-service science teachers were negative about the giftedness of the gifted in science. Second, they recognized that various types of classes were not provided. Especially, while theoretical lectures were mostly offered, they recognized that it had a negative influence in developing the potential giftedness of the gifted in science. Third, they were negative about the absence of programs for improving creativity and thinking skills and teaching materials for the gifted in science; however, they were positive about self-directed learning. Fourth, they had a negative opinion on educational facilities and the number of students in classes. Fifth, they recognized that potential giftedness would be developed the most when the lecturer is a professor majoring in the subject. For improvements in the classes for the gifted in science, they referred to revising the distinction focusing on preceding learning, reinforcing teaching methods to improve creative thinking, constructing creative contents regardless of specific grades and curriculum, securing learning materials for the gifted, and the necessity of lecturers specialized in the education for the gifted. Eventually, pre-service science teachers have negative cognitions for the classes for the gifted in science offered by universities, and it was known that they mentioned the necessity of creative educational courses and professional lecturers, not pre-learning for improvements.