• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.1
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• pp.45-53
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• 2014

In strength limit states design, it is assumed that after cracking, reinforcement carries all tension in the tension zone of reinforced concrete members. However, it can be seen the concrete between cracks will contribute to carrying a part of the tension stress in actual concrete members particularly at service load levels, this effect is referred as tension stiffening effect. In this study, tension stiffening models and high strength concrete beam flexural test results were verified through comparison. The relationship between moment-curvature and load-deflection was evaluated by result of tension stiffening model and test result values. The analysis results showed that ACI 318 and Owen & Damjanic generally shows good agreement.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.4
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• pp.305-312
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• 2014

The current American Concrete Institute(ACI), Canadian Standard Associate(CSA) and CEB-FIP Model Code 2010 provisions on the shear strength of a simply supported deep beam suggest that deep beams should be designed using the strut-and-tie model. Although this is a useful methodology to design members in disturbed regions, the quality of the design is highly dependent on the truss model that designers create. However, Hong et al. derived the shear strength equations of reinforced concrete deep beams. This thesis investigates the validity of the current ACI, CSA and CEB-FIP code provisions on the shear strength of simply supported reinforced concrete deep beams by comparing them with the shear strength equations proposed by Hong et al. The comparison shows that all of these code provisions provide reasonable estimates on the shear strength of concrete deep beam members and the selection of an internal truss model plays an important role on the estimation of shear strength.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.2
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• pp.84-93
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• 2008

Modeling and rendering of cloth texture have been regarded as one of the most important factors to enhance reality of the contents in the digital contents industry. So far, however, two major approaches to realistically describe the cloth texture were developed: building analytical reflectance model for target cloth and sometimes thread itself and obtaining overall reflectance model using optical equipments. However, yielding a plausible analytic reflection model satisfying many subtle characteristics of a cloth is not an easy task; moreover, fine-detailed modeling of the cloth pattern across the target clothes should also be accompanied by huge amount of computation. The method to obtain overall reflectance model needs expensive measurement equipments and data size becomes huge. Since it applies in the end the reflectance model obtained at one point of a cloth to across whole the visible area of the target clothes, it cannot properly reproduce the pattern of the clothes nor the texture. To address the aforementioned problems, this paper proposes a simple low cost camera rig and a novel method for realistic modeling and rendering of the cloth texture by analyzing photos taken by the proposed camera rig, which can reproduce even the texture pattern applied to the whole clothes, overcoming the one-point reflectance model.

• Tunnel and Underground Space
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• v.29 no.5
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• pp.356-366
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• 2019

Various TBM performance prediction models have been developed and most of them were considered penetration rate only. Despite the fact that some models have suggested equations and charts for estimating the utilization factor, but there are a few studies to estimate the TBM utilization factor. Utilization factor is affected by the type of TBM machine, operation, maintenance of machine, geological conditions, contractor experience and other factors. In this study, more than 100 case studies are analyzed to determine the relationship between the utilization factor and RMR, geological conditions, TBM types, tunnel length, and TBM diameter. Simple and multiple linear regression analysis are performed to develop predictive models for the utilization factor. The predictive model with explanatory variables of geological conditions, TBM types, tunnel length, and TBM diameter does not give a good correlation. The predictive models with explanatory variable of RMR give higher values of the coefficient of determination.

• Journal of the Korean Solar Energy Society
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• v.25 no.1
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• pp.97-104
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• 2005

A one-dimensional heat transfer model for the vertical borehole system is derived in this study to predict the thermal behavior of the system and surrounding soil. In this model the U-tube is replaced with one effective tube of effective diameter which is surrounded by concentric grout region. All thermal resistances of borehole are counted in the grout region with effective thermal conductivity of grout. Effective thermal conductivity of grout and sand are calculated through parameter estimation. The validity of this model is accomplished through comparison of the predicted temperature profiles of the model with experimental data.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2005.04a
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• pp.291-294
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• 2005

본 해석은 제철용 고로 구조물에 대해여 고로 내의 온도 분포를 이용한 열전도 유한요소 해석을 수행하고자한다. 해석모델인 고로는 내화벽돌, 냉각판, 내화재(castable), 철피의 복잡한 구조로 이루어져있다. 각각의 재료뿐만 아니라 고로에 사용되어지는 모든 내화벽들의 재료 물성치 값을 사용하여 보다 실직적인 해석을 수행하고자 하며 고로의 냉각 시스템인 냉각판과 냉각 pipe의 효과 규명하고자 한다. 어떠한 부분 모델이 아니라 고로 전체를 대상으로 열전도 해석을 수행한다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.525-528
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• 2009

FE 해석은 구조물의 고유진동수 판단 및 거동 예측 등에 사용되며 따라서 실구조물과 동일하게 FE 해석모델을 작성할수록 실제 구조물의 고유진동수 및 거동을 정확하게 예측할 수 있다. 그러나 실 구조물과 동일하게 모델링 하는 것이 어렵기 때문에 FE 해석을 통해 예측한 구조물의 고유진동수와 실제 구조물의 고유진동수는 차이가 발생한다. FE 해석을 통한 고유진동수에 대하여 정확성을 판단할 수 있는 방법은 실제 계측을 통하여 얻은 고유진동수와 비교하는 것이다. 따라서 본 연구는 미진동하의 구조물에 대하여 계측을 실시함으로써 대상건물의 고유진동수를 파악하고, 실제 고유진동수에 대한 FE 해석의 고유진동수 비교를 통하여 FE 해석의 정확도를 판단하였다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.521-524
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• 2009

구조물의 동적특성은 FE 해석에 의해 주로 평가된다. 따라서 실제 구조물과 유사하게 모델링 될수록 구조물의 동적특성을 실제 동적특성에 보다 부합되게 예측할 수 있다. 그러나 FE model을 실제 구조물의 조건과 동일하게 작성하는 것이 어렵고 또한 모델의 정확성을 정량적으로 판단하기가 어렵다. 따라서 본 연구에서는 벽식아파트에 대하여 계측을 실시하고 실제 구조물의 동적특성을 분석하였다. 분석결과를 바탕으로 FE 해석결과와 비교함으로써 FE model의 정확성을 판단하는 한편 실 구조물과 근사하게 FE model의 보정방안을 제시하였다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2005.11a
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• pp.283-289
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• 2005

Background Subtraction은 움직이는 물체 검출에 가장 많이 사용되는 방법 중 하나이다. 배경이 복잡하고 변화가 심한 경우, 배경을 실시간으로 얼마나 정확하게 학습하는가가 물체 검출의 정확도를 결정한다. Gaussian Mixture Model은 이러한 배경의 모델링에 가장 많이 쓰이는 방법이다. Gaussian Mixture Model은 확률적 학습 방법을 사용하는데, 이러한 방법은 물체가 자주 지나다니거나 물체가 멈춰있는 경우, 배경을 정확하게 모델링하지 못한다. 본 논문에서는 밝기 값에 대한 확률적 모델링과 밝기 값의 변화에 따른 처리를 결합하여 혼잡한 환경에서 배경을 정확하게 모델링할 수 있는 학습 방법을 제안한다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.5
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• pp.93-98
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• 2005

An Engineering Model(EM) of the Telemetry-Command Unit(TCU) for STSAT-2 was developed. The TCU of STSAT-2 has some improved features compared with that of STSAT-1. To reduce weight and size of TCU all logics are implemented in FPGA without CPU. EM I&T(Integration and Test) was successfully performed with no errors.