• Journal of the Society of Disaster Information
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• v.11 no.1
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• pp.9-22
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• 2015

School is the place where teenagers spend most of their time, forming friendships and receiving guidance from the teachers. Their life in school is a procedure of learning lessons before advancing into the society. However, in this place of learning, misdeeds such as violence, extortion and bullying are actually happening, some of which developing into suicide, murder and prostitution. For this reason, violence in school, especially, raises concerns as a serious social problem these days. Therefore, this study suggests more practical improvement programs to solve the problem of the violence in school, by first investigating the concept and the actual situation of school violence, and by better understanding the problems resulted from the school violence. The researchers of the study suggest as follows: First is about strengthening the education that builds students' personality, where we investigate the methods of personality education that suit with the current situation and suggest what is necessary to improve them. The second is about expansion of the functioning of families and of the educational role of the household heads, where we argue the importance of education in the family in addition to the education in school, and we suggest the right way for the parents to discipline their children. The third is about expansion of counseling professionals and improving social environment, where we explain the importance of counseling professionals in preventing and solving the issues in school violence and suggest expansion of these professionals and also suggest installation and operation of dedicated counseling room in schools. The fourth is about use of school sheriffs, where we suggest dispatching school sheriffs nationwide and fully use them as a countermeasure against school violence.

• Journal of Korean Society of Steel Construction
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• v.9 no.4 s.33
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• pp.579-588
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• 1997

During the construction of cable stayed bridge, errors are always caused by various reasons, accumulated and amplified through the complex construction steps. It is likely that the undesirable stress distribution of members and the large deflection of the bridge different from design values come out The adjustment of cables during construction is absolutely indispensable to correct the stress distribution of the members and the geometrical configuration of the bridge. In the conventional method, weight coefficients are used to consider the difference of units between cable forces and girder deflections during the optimization process of cable adjustment. However, it is not easy to determine weight coefficients and the adjustment must be repeated several times with the time consuming process of the determination of new weight coefficients in case that errors are out of design allowable limits. In this paper, fuzzy linear regression analysis is applied to the cable adjustment to overcome those problems. In the application of fuzzy linear regression analysis method the designer's intention and the design allowable limits can be formulated in the form of the constraints of the linear optimization problem. Therefore, the cable adjustment in construction site can be carried out with the fuzzy linear regression analysis more rapidly than with the convetional method.

• Journal of Korean Society of Steel Construction
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• v.19 no.1
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• pp.15-27
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• 2007

Over the past decade, labor costs have increased relative to the cost of material hardware according to analysts in the construction industry. Therefore, the minimum weight design, which has been widely adopted in the literature for the optimal design of steel structures, is no longer the most economical construction approach. Presently, although connection- related costs is crucial in determining the most cost-effective steel structures, most studies on this subject focused on minimum-weight design or engaged in higher analysis. Therefore, in this study, we proposed a fabrication scheme for the most cost-effective moment-resisting steel frame structures that resist lateral loads without compromising overall stability. The proposed approach considers the cost of steel products, fabrication, and connections within the design process. The optimal design considered construction realities, with the optimal trade-off between the number of moment connections and total cost was achieved by reducing the number of moment connections and rearranging them using the combination of analysis that includes shear, displacement and interaction value based on the LRFD code and optimization scheme based on genetic algorithms. In this study, we have shown the applicability and efficiency in the examples that considered actual loading conditions.

• Journal of Korean Society of Steel Construction
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• v.20 no.6
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• pp.701-709
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• 2008

Owing to the decreased work term and the convenience of construction work in Korea, the steel deck plate system has been widely used in the construction field. Most of all, due to its good stiffness and economic consideration, the steel-wire-integrated deck plate system (or truss deck plate system) has become very popular in recent years. But although it has many advantages, the truss deck plate system has a critical defect: it gets rusty in the welding joints between the lattice steel wire and the deck plate, resulting in the cracking of such welding joints and water leakage. To address these problems, a new type of truss deck plate system, which need not be welded and does not rust, was proposed herein: the TOX deck plate system. In this study, tests were conducted on 15 specimens to evaluate the structural safety of the proposed deck plate system during the construction stage. The test parameters were as follows: the depth of the slab the length of the span the diameters of the top, bottom, and lattice steel wire and the material properties of the zinc-coated steel sheets. The test results show that the TOX deck plate system can guarantee structural safety owing to its deflection and strength.

• Journal of Korean Society of Steel Construction
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• v.23 no.6
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• pp.705-713
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• 2011

This study was conducted to assess the vibration capacity and the fire resistance capacity of a deck plate slab using an omega steel plate as the void deck plate. First, to evaluate the vibration capacity of the deck plate slab after the insertion of the omega steel plate, three 150mm specimens and three 200mm specimens were made using the slab depth as the main variable. Each specimen consisted of an existing deck plate and two specimens, using the topping depth as the variable according to the slab depth. Second, two real-size specimens were made to evaluate the fire resistance capacity. The results of the test showed that the steel-wire-integrated deck plate slab that was inserted in the omega steel plate did not have a vibration problem due to the void deck plate, because the natural frequency was 12.66-14.09 Hz in the vibration test, and each specimen satisfied the appraisal standards for the load capacity, heat block quality, and chloride inhibition for two hours in the fire resistance test. Consequently, the steel-wire-integrated deck plate slab that was inserted in the omega steel plate can be reduced using the concrete volume and can have higher vibration and fire resistance capacities, similar to the existing deck plate.

• Proceedings of the KAIS Fall Conference
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• 2010.05b
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• pp.1209-1212
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• 2010

본 연구는 제주지역 일부 초, 중학생들의 간접흡연 실태와 그로 인한 현재 흡연 여부 관계를 분석하여 초, 중학생들의 흡연 예방 교육 계획 및 수립에 기초 자료를 제공하고자 본 연구를 시도하였다. 자료 수집 기간은 2009년 6월 29일부터 7월 11일까지 제주특별자치도내 초등학교 5, 6학년 아동 464명과 중학생 475명을 대상으로 설문지를 이용하여 조사하였다. 연구 대상자들의 간접흡연 노출 관련성은 가정불화, 성적, 친구관계스트레스가 있는 대상자에게서 높게 조사되었고, 가족 및 주변인의 흡연유무에 따른 간접흡연 실태는 부모 및 친구의 흡연으로 간접흡연에 노출되었으며 통계적으로 유의한 차이를 보였다. 간접흡연의 주제공자는 아버지며, 주 간접흡연 피해 장소는 집으로 나타났다. 간접흡연 노출 유무를 종속변수로 한 로지스틱 회귀분석 결과는 흡연하는 아버지를 둔 대상자가 그렇지 않은 대상자에 비해 간접흡연 노출이 높았으며, 흡연하는 친구를 둔 대상자는 그렇지 않은 대상자에 비해 간접흡연 노출이 높게 나타났다. 현재흡연 여부를 종속변수로 한 로지스틱 회귀분석의 결과는 남학생이 여학생에 비해, 중학생이 초등학생에 비해 현재흡연율이 높았고, 엄한 가정 분위기 속에서 생활하고 있는 대상자와 흡연하는 친구를 둔 대상자는 그렇지 않은 대상자에 비해 현재흡연율이 높았으며, 간접흡연에 노출 되었던 대상자에게서 현재흡연율이 높게 나타났다. 이상의 결과를 종합하여 볼 때 초, 중학생의 간접흡연 실태는 심각한 사회문제이다. 또한 대상자들의 현재 흡연은 간접흡연 노출과 관련이 있는 것으로 볼 수 있었다. 이러한 간접흡연의 노출 및 그로 인한 흡연율을 줄이기 위해서는 가정 및 학교와 공공장소 등에서 간접흡연에 노출되지 않는 제도적 및 환경적인 조치들이 우선되어야 할 것이며, 학생들을 대상으로 간접흡연에 대한 간접흡연 예방 교육 및 대처방안 교육이 조기에 지속적으로 실시되어야 하겠다. 또한 유치원에서부터 고등학교에 이르기까지 모든 학생들에게 필수적으로 흡연예방 교육을 수강하게 하고, 교사들을 위한 연수교육 실시, 학교 흡연예방사업에 부모나 가족을 참여, 흡연예방 사업의 정기적인 평가 실시 등 국가적인 정책이 동반되어야 할 것이다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.3
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• pp.201-209
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• 2002

Crib wall system is one of segmental crib type wall. Crib walls are constructed from separate members with no bonds between them other than frictional. The wall units are divide into two main types termed headers and stretchers. The headers run from the front to the back of the wall, perpendicular to the wall face. The cells are created by forming a grid by stacking individual wall components known as headers and stretchers. The body of wall consists of a system of open cell which are filled with a granular material. The design of crib retaining wall is usually based on conventional design methods derived from Rankine and Coulomb theory so that is able to resist the thrust of soil behind it, because it may be assumed that the wall acts as a rigid body. However, deformation characteristics of crib walls cannot be assumed as monolithic. They consist of individual members which have been stacked to creat a three dimensional grid. Therefore, the segmental grid allows relative movement between the individual member within the wall. The three dimensional flexible grid leads to stress distribution by interaction behavior between soil and crib wall. Therefore, in this study, in order to analysis the trends of deflection of crib wall system, new numerical models based on the results of Brandl's full scale test are introduced for design concept.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.5
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• pp.137-147
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• 2012

In the steel-free bridge concrete deck, steel straps are generally used instead of conventional steel rebar while laterally restrained in the perpendicular direction to the traffic in order fir the arching effect of concrete deck. In this paper, the minimum amount of FRP bar is to be suggested based on the structural strength, crack propagation, stress level and others in order to control cracks. As a result of laboratory tests, the structural strength of deck with 0.15 percentage of steel strap showed improved structural strength including ductility. The long-term serviceability of steel strap deck with FRP bar proved to satisfy the requirements and to be structurally stable while showing the amount of crack and residual vertical displacement within the allowable limits after two million cyclic loadings. The structural failure of RC bridge deck is generally caused from the punching shear rather than moment. Therefore, the ultimate load at failure could be estimated using the shear strength formula in the two-way slab based on ACI and AASHTO criteria. However the design criteria tend to underestimate the shear strength since they don't consider the arching effects and nonlinear fracture in bridge deck with lateral confinement. In this paper, an equation to estimate the punching shear strength of steel strap deck is to be developed considering the actual failure geometries and effect of lateral confinement by strap while the results are verified in accordance with laboratory tests.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.5
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• pp.116-127
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• 2014

The studies were carried out to process one cycle for a day to the large section tunnel lining concrete. Climatic characteristics of the tunnel inside are changed, when the temperature of the concrete placement is low, the mold remove time is increased that the heat of hydration speed be delayed because affects the strength development, to compensate for this, after installing the curing sheet on both sides of the steel form and installation of tunnel entrance, when it comes to providing the additional heat source of $28{\pm}2^{\circ}C$ therein, it was to be achieved early strength development control standards (4.5MPa) presented as a crack control scheme or more, thus, It was able to remove after age of 14hr from mold. On the other hand, under the conditions of $10{\pm}1^{\circ}C$ that a natural curing temperature in the tunnel, it was analyzed must ensure the curing time of 36hr or more after concrete placement. Throughout this study, the concrete strength development and the temperature in the early-age concrete, it can find that reverify the curing temperature is greatly affected, even concrete fly ash is mixed 10%, if it is possible to raise the surface temperature for a predetermined time, is not a problem in the early strength development.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.5
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• pp.82-90
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• 2018

The nuclear structures are composed of large diameter bars over No.36. If the hooked bars are used for anchorage of large diameter bars, too long length of the tail extension of the hook plus bend create congestion and make an element difficult to construct. To address those problems, headed bars were developed. Provisions of ACI 318-08 specify the development length of headed bars and ignore the effect of transverse reinforcement based on the background researches. However, if headed bars are used at the cut-off or lap splice, longitudinal reinforcements, which are deformed in flexural members, induce tensile stress in cover concrete and increase the tensile force in the transverse reinforcement. The object of this research is to evaluate the effects of transverse reinforcement on the anchorage capacity of headed bar so anchorage test with variable of transverse rebar spacing was conducted. Specimens, which can consider the behavior at the cut-off, were tested. Test results show that failure of specimen without transverse reinforcement was sudden and brittle with concrete cover lifted and developed stress of headed bars was less than half of yield strength of headed bars. On the other hand, in the specimen with transverse reinforcement, transverse rebar directly resist the load of free-end so capacity of specimens highly increased.