• Journal of Korean Society of Steel Construction
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• v.13 no.2
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• pp.153-162
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• 2001

A direct design method of three-dimensional frames using practical advanced analysis is presented. In this method. separate member capacity checks encompassed by the code specifications are not required. because the stability of separate members and the structure as a whole can be rigorously treated in determining the maximum strength of the structures. Advanced analysis accounts for geometric and material nonlinearities. The geometric nonlinearlity is considered by the use of stability function. The material nonlinearity is accounted for using CRC tangent modulus and parabolic function. The load-displacements predicted by the proposed analysis compare well with those given by other approaches. A design example has been presented for a 22-story frame. The analysis results show that the proposed method is suitable for adoption in practice.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.4
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• pp.161-167
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• 2008

In this paper, the optimal design of trusses using advanced analysis and genetic algorithm is performed. An advanced analysis takes into account geometric nonlinearity and material nonlinearity. The micro genetic algorithm is used as optimization technique. The weight of structures is treated as the objective function. The constraint functions are defined by load-carrying capacities and displacement requirement. The effectiveness of the proposed method is verified by comparing the results of the proposed method with those of other method.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.5
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• pp.203-211
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• 2006

In this paper, the optimization of direct design system of steel frames by genetic algorithm involving advanced analysis are performed. For the analysis of steel frames advanced analysis accounting for geometric nonlinearity and material nonlinearity are executed. The genetic algorithm was used as optimization technique. The weight of structures is treated as the objective function. The constraint functions are defined by load-carrying capacities, deflections, inter-story drifts, and ductility requirement. The effectiveness of the proposed method are verified by comparing the results of the proposed method with those of other method.

• Journal of Korean Society of Steel Construction
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• v.18 no.6
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• pp.707-716
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• 2006

The optimization of the direct design system of semi-rigid steel frames using advanced analysis and genetic algorithm was presented. Advanced analysis can predict the combined nonlinear effects of connection, geometry, and material on the behavior and strength of semi-rigid frames. Geometric nonlinearity was determined using stability functions. On the other hand, material nonlinearity was determined using the Column Research Council (CRC) tangent modulus and parabolic function. The Kishi-Chen power model was used to describe the nonlinear behavior of semi-rigid connections. The genetic algorithm was used as the optimization technique. The objective function was assumed as the weight of the steel frame, with the constraint functions accounting for load-carrying capacities, deflections, inter-story drifts and ductility requirement. Member sizes determined by the proposed method were compared with those derived using the conventional method.

• Journal of Korean Society of Steel Construction
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• v.17 no.1 s.74
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• pp.13-21
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• 2005

Advanced analysis and optimal design of steel arch bridges is presented. In the design method using an advanced analysis, separate member capacity checks after analysis are not required because the stability and strength of the structural system and its component members can be rigorously treated in the analysis. The geometric nonlinearity is considered by using the stability function. The Column Research Council tangent modulus is used to account for gradual yielding due to residual stresses. A parabolic function is used to represent the transition from elastic to zero stiffness associated with a developing hinge. An optimization technique used is a modified section increment method. The member with the largest unit value evaluated by AASHTO-LRFD interaction equation is replaced one by one with an adjacent larger member selected in the database. The objective function is taken as the weight of the steel arch bridge and the constraint functions account for load-carrying capacities and deflection requirements. Member sizes determined by the proposed method are compared with those given by other approaches.

• Journal of Korean Society of Steel Construction
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• v.16 no.5 s.72
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• pp.683-694
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• 2004

Advanced analysis and optimal design of semi-rigid space steel frames were presented. The advanced analysis can predict the combined nonlinear effects of connection, geometry, and material on the behavior and strength of semi-rigid frames. The Kishi-Chen power model was used to describe the nonlinear behavior of semi-rigid connections. Geometric nonlinearity was determined using stability functions. Material nonlinearity was determined using the Column Research Council (CRC) tangent modulus and the parabolic function. The direct search method proposed by Choi and Kim was used as optimization technique. One by one, the member with the largest unit value evaluated using the LRFD interaction equation were placed adjacent to a larger member selected from the database. The objective function was assumed to be the weight of steel frame, while the constraint functions were load-carrying capacities, deflections, inter-story drifts, and the ductility requirements. The member sizes determined using the proposed method were compared to those derived from the conventional LRFD method.

• Journal of Korean Society of Steel Construction
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• v.15 no.6 s.67
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• pp.661-672
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• 2003

The advanced analysis and optimal design of semi-rigid frame were presented. Advanced analysis can predict the combined nonlinear effects of connection, geometry, and material on the behavior and strength of semi-rigid frames. The Kishi-Chen power model was used to describe the nonlinear behavior of semi-rigid connections. Geometric nonlinearity was determined using stability functions. On the other hand, material nonlinearity was determined using the Column Research Council (CRC) tangent modulus and parabolic function. The direct search method proposed by Choi and Kim was used as optimization technique. The member with the largest unit value evaluated using the LRFD interaction equation was replaced one by one with an adjacent larger member selected from the database. The objective function was assumed as the weight of steel frame, with the constraint functions accounting for load-carrying capacities, deflections. inter-story drifts, and ductility requirement. Member sizes determined by the proposed method were compared with those derived using the conventional LRFD method.

• Communications of Mathematical Education
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• v.19 no.2 s.22
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• pp.445-452
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• 2005

본 연구는 중 고등학교 교사 50명에 대하여 기하 문제의 논증기하적 또는 해석기하적 문제해결 전략이 학생들의 평가에 어떤 영향을 미치는가를 조사한 것이다. 중학교에서 고등학교로 진학하면 도형의 문제에 대한 해석기하적인 문제해결 능력은 교육과정 상 대단히 중요하게 가르쳐야 할 내용이다. 유클리드 기하에 바탕을 둔 논증기하의 지식은 좌표평면의 도형을 방정식으로 나타내고 연구하는 해석기하의 기본이다. 그럼에도 불구하고 많은 학생들은 논증기하적 문제해결을 선호하는 반면 해석기하적 문제해결은 어려워한다. 또한 논증기하적 문제 형태에는 논증기하적 문제해결 전략, 해석기하적 문제 형태에는 해석기하적 문제해결 전략을 구사하는 경향을 보인다. 본 연구는 중 고등학교 교사들의 기하 문제에 대한 내용 지식이 학생 평가에 미치는 영향에 초점이 맞추어져 있다.

• Journal of the Korean earth science society
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• v.31 no.4
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• pp.378-391
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• 2010

The purpose of this study was to investigate the graph interpretation ability and perception of high school students and preservice secondary teachers in Earth science. We developed two different instruments; one was a graph interpretation ability inventory that consists of 9 graph types with 18 items, and the other one is two questionnaires to explore the participants' perception about Earth science-related graph. The results of this study are as follows: High school students and preservice secondary teachers demonstrated their remarkable ability in interpreting a line graph, but showed their limited ability with the graph of overlapped and directional change, which means the graph interpretation ability was affected by a graph type; two groups participated in this study revealed a considerable difference in the graph interpretation ability depending on the grade level; preservice teachers were superior to high school students in discriminating two graphs, the representation method, which are different with the same topic; and many participants in both groups considered that the property of Earth science graph was considerably different from that of other science subjects, especially in directional change graph, scatter graph, contour map, and domain graph. The results suggest that the effective graph instruction strategies be developed in Earth science learning.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.1
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• pp.101-113
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• 2013

This paper intends to develop mechanical analysis models that are able to predict complete nonlinear behavior in the bolted connector subjected to cyclic loads. In addition, experimental data which were obtained from loading tests performed on the T-stub connections are utilized to validate the accuracy of analytical prediction and the adequacy of numerical modeling. The behavior of connection components including tension bolt uplift, bending of the T-stub flange, stem elongation, relative slip deformation, and bolt bearing are simulated by the multi-linear stiffness models obtained from the observation of their individual force-deformation mechanisms in the connection. The component springs, which involve the stiffness properties, are implemented into the simplified joint element in order to numerically generate the behavior of full-scale connections with considerable accuracy. The analytical model predictions are evaluated against the experimental tests in terms of stiffness, strength, and deformation. Finally, it can be concluded that the mechanical models proposed in this study have the satisfactory potential to estimate stiffness response and strength capacity at failure.