• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.8 no.2
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• pp.45-51
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• 1990

DEM must have a high accuracy against the actual topographic model. A model which can compute heights responding to random plane position by using of the topographic data and interpolation must be constructed. Interpolation affected by the accuraccy of the observations included noise, which affected by the slop and curvature weight. Data smoothing is a method to reduce the noise. Average declination and area ratio are variable which result similarity in according to slope. But in local area, area ratio well shows a local change. This study try to classify the terrain by the declination to analysis the effects of the declination and curvature weights, and then to represent the most probable model. The result are following : In terrain classification by the slop, p16 and p24 were fitted in the plane surface fit p16 and S in the varying surface, and S and p24 in the irregular surface in classification by curvature, p24 and S were fitted in the plane or varying surface, and p16 in the irregular surface In case of hybrid, p16, p24 and S are fitted in the plane, varying and irregular surface respectively. Smoothing is the most effective in case of slope of 50 persentage and of curvature weight of 0.0015.

• Journal of the Society of Disaster Information
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• v.19 no.3
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• pp.572-581
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• 2023

Purpose: The purpose of this study is to improve the irregularity of the stress-strain curve and to ensure accuracy when calculating the damping effect by preventing members from moving in the off-plane direction due to eccentricity when loads are applied. Method: The specifications of the steel strips used in this study are the same, but the curvature of the strips to constitute each damper is different. Each steel strip with different curvature was arranged in an triangle, three dampers with different curvature were made, and repeated load tests were conducted, and the amount of energy dissipation was calculated to measure the performance of the damper. Result: The amount of energy dissipation significantly decreases compared to the case where there is no initial curvature, and the change in the test energy dissipation amount according to the size of the curvature is not large, and the presence or absence of the hyperbolic rate is considered an important variable. Conclusion: The period is about 78.7% longer from T=0.3 to T=0.536sec, and the response spectrum acceleration is reduced from Sa=0.54g to Sa=0.229g, so the damping effect of the damper is sufficient.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.4
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• pp.142-149
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• 1996

Pyramid type three roll bending machines are widely used in roll-bending process to produce singly curved plate. In forming singly curved plate, controlling the vertical displacement of the center roller is most important to acquire the shape required and automation system of the process. In this paper roller bending process is modeled as an elastic-plastic phenomenon and analyzed using beam theory and finite element method. In finite element analysis the workpiece is modeled by using beam elements and plane strain elements respectively. Through the analyses vertical center roller displacement is obtained to get constant curvature distribution along arc length. The relationship between center roller displacement and curvature in steady state as well as residual stress and strain along plate thickness direction are calculated through finite element analysis.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.4
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• pp.51-61
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• 2003

This research is a park of a research program to develope a new design method for reinforced concrete bridge columns under axial load and cyclic lateral load. The objectives of this paper are to investigate the relationship between curvature ductility and displacement ductility and to propose a correlation equation for designing of reinforced concrete bridge columns under axial load and cyclic lateral load. Computer program NARCC was used for parametric study, which was proved to provide good and conservative analytical result especially for deformation capacity and ductility factor compared with test result. A total of 7,200 spirally reinforced concrete columns were selected considering the main variables such as section diameter, aspect ratio, concrete strength, yielding strength of longitudinal and confinement steel, longitudinal steel ratio, axial load ratio, and confinement steel ratio. A new equation between curvature ductility factor displacement ductility factor with the aspect ratio was proposed by investigation of 21,600 data produced from the selected column models by applying 3 different definitions of yield displacement.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.6
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• pp.521-532
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• 2007

In the derivation of mild slope equation, a Galerkin method is used to rigorously form the Sturm-Liouville problem of depth dependent functions. By use of the canonical transformation to the dependent variable of the equation a reduced Helmholtz equation is obtained which exclusively consists of terms proportional to wave number, bottom slope and bottom curvature. Through numerical studies the behavior of terms is shown to play an important role in wave transformations over variable depth and it is proved that their relative magnitudes limit applicability of the mild slope equation(MSE) against the modified mild slope equation(MMSE).

• Proceedings of the KAIS Fall Conference
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• 2011.12b
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• pp.525-528
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• 2011

1400cc급 발전용 엔진 트로틀 바디의 최적화 및 성능 향상을 위하여 유동해석을 수행하였다. 베르누이 정리를 기본으로, 성능을 발휘하는 주요 설계인자인 트로틀 바디 내부의 트로틀 밸브 각도 및 흡기부 곡률 등을 설계 변수로 유동해석을 수행하였다. 벤튜리관 흡입부의 곡률을 증가시켜 트로틀 바디에서 소모되는 흡기저항을 줄였다. 감소된 흡기저항은 펌핑로스를 저감하여 연비향상에 도움이 될 것으로 기대된다. 결과적으로 해석결과 분석을 통하여 최적화된 모델을 제시하였다.

• Proceedings of the KAIS Fall Conference
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• 2006.11a
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• pp.261-264
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• 2006

본 논문에서는 다양한 곡률반경의 연속에 의하여 살 두께 차가 큰 사출성형품에 불균일한 수축으로 인한 변형이 생성되어 이를 방지하기 위한 적정 CAE 냉각설계를 수행하였다. SAN 및 PMMA 재질의 Jar용기에 대한 균일냉각구조와 최적성형조건을 금형설계에 적용하고자 사출성형의 중요인자인 사출압력, 수지온도, 금형온도, 냉각조건 등을 moldflow 프로그램을 활용하여 연구를 수행하였다. 연구결과로서, 적정 변수인 사출압력 상승, 수지온도 낮춤, 급속냉각으로 후로우 등의 불량현상을 분석하였고 변형 및 불량을 극소화시킬 수 있는 냉각구조와 사이클 시간을 단축시킬 수 있는 사출성형조건을 제시하였고 적정 냉각모듈로부터 냉각시간을 단축하였다.

• Journal of the Korea Concrete Institute
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• v.26 no.2
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• pp.159-169
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• 2014

This study generalizes the lateral load-displacement relationship of reinforced concrete shear walls from the section analysis for moment-curvature response to straightforwardly evaluate the flexural capacity and ductility of such members. Moment and curvature at different selected points including the first flexural crack, yielding of tensile reinforcing bar, maximum strength, 80% of the maximum strength at descending branch, and fracture of tensile reinforcing bar are calculated based on the strain compatibility and equilibrium of internal forces. The strain at extreme compressive fiber to determine the curvature at the descending branch is formulated as a function of reduction factor of maximum stress of concrete and volumetric index of lateral reinforcement using the stress-strain model of confined concrete proposed by Razvi and Saatcioglu. The moment prediction models are simply formulated as a function of tensile reinforcement index, vertical reinforcement index, and axial load index from an extensive parametric study. Lateral displacement is calculated by using the moment area method of idealized curvature distribution along the wall height. The generalized lateral load-displacement relationship is in good agreement with test result, even at the descending branch after ultimate strength of shear walls.

• Journal of Korean Society of Steel Construction
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• v.14 no.6
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• pp.803-811
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• 2002

Current composite steel and concrete bridges are designed using full-interaction theory assuming there is no relative slip, between the steel and concrete components along their interface, because of the complexities of partial-interaction analysis techniques. However, in the assessment of existing composite bridges this simplification may not be warranted as it is often necesary to extract the correct capacity and endurance from the structure. This may only be achieved using partial-interaction theory which tuly reflects the behaviour of the structure. In this paper, Parametric analyses have been carried out in order to confirm the partial-interaction curvatures with deflection effect using the finite element method. Therefore, the model is considered for simply supported steel and concrete composite bridges with a uniform distribution of connectors subjected to a single concentrated load. For the case studies, this study applicate a parameters such as the number and space of stud shear connector and elastic modulus of concrete slabs. From this study, it is known that partial-interaction effect was in the increase to the increasing the deflection of composite bridges, and stiffness and strength of slab concrete considering the occurrence of crack effect seriously to the partial-interaction behavior.

• Journal of Korean Society of Steel Construction
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• v.24 no.2
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• pp.175-188
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• 2012

A parametric study for varying the radii of curvature is performed with a curved tub girder bridge having three continuous spans. The bracing forces of top lateral bracings from the results of numerical equations are compared to those of 3-dimensional finite element analyses. New modifying factors applicable in computing the nominal member forces of top lateral bracings were suggested. The numerical equations were derived based on one girder system, and it is shown that the numerical equations exhibit some errors compared with 3D FEA results. The main reason for this phenomenon lies on the number of girders. The twin girder system has an external cross-beam between inner and outer girder. It also has larger lateral stiffness than the single girder system. Finally, the distributions by the torsion, bending, distortion, and lateral loading of the top lateral bracing forces were presented in this paper.