• Title, Summary, Keyword: 유사 동적 실험

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Implicit Time Integration Scheme for Real-Time Hybrid Test System (실시간 하이브리드 실험 시스템을 위한 Implicit 시간적분법)

  • Jung, Rae-Young
    • Journal of the Earthquake Engineering Society of Korea
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    • v.10 no.5
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    • pp.99-106
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    • 2006
  • The Real-Time Hybrid Test system presented in this paper is based on the pseudodynamic test method, and it combines physical testing with model-based simulation. The system is designed to achieve a rate of loading that is significantly higher than that of a conventional pseudodynamic test approaching the real-time response of a structure subjected to earthquake loads. To provide robust computation environment for the analysis of many degree-of-freedom structures, the system adopts an implicit time integration scheme in the model-based simulation. This paper presents an overview of the developed system and numerical simulations that were conducted to evaluate the performance of the computation scheme adopted here. Results of these studies have demonstrated the good performance of the computation scheme for real-time multiple-degree-of-freedom tests.

Sorption Characteristics of Arsenic on Furnace Slag by Adsorption Isotherm and Kinetic Sorption Experiments (등온 및 동적 흡착 실험을 통한 제강 슬래그의 비소 흡착 특성)

  • Oh, Cham-Teut;Rhee, Sung-Su;Igarashi, Toshifumi;Kon, Ho-Jin;Lee, Won-Taek;Park, Jun-Boum
    • Journal of the Korean Geotechnical Society
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    • v.26 no.9
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    • pp.37-45
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    • 2010
  • Sorption characteristics of arsenic on furnace slag were investigated to remove arsenic from groundwater using furnace slag, which is industrial waste generated from steel company. Adsorption isotherm experiments and kinetic sorption experiments were performed and the chemical characteristics of supernatants from these experiments were analyzed. Results showed that all supernatants were alkaline (above pH 9) and the highest ion concentration in the solution was found with calcium (30~50 mg/L). Results of adsorption isotherms were more adequately described by the Freundlich model than Langmuir model. From adsorption isotherms experiments, it was noted that the adsorption amount of As(V) was 87% higher than that of As(III). Results of kinetic sorption experiments were more properly fitted by pseudo second order (PSO) model than pseudo first order model. Equilibrium adsorption amount ($q_e$) and relaxation time ($t_r$) calculated from PSO model increased with initial concentration of arsenic. Equilibrium adsorption amount of As(V) was higher than that of As(III) and relaxation time of As(V) was shorter than that of As(III). Adsorption isotherm results could be predicted by kinetic adsorption results, since equilibrium adsorption amount calculated through PSO model generally agreed with equilibrium adsorption amount measured from adsorption isotherm.

An Equivalent Multi-Phase Similitude Law for Pseudodynamic Test on Small-scale RC Models (RC 축소모형의 유사동적실험을 위한 Equivalent Multi-Phase Similitude Law)

  • ;;;Guo, Xun
    • Journal of the Earthquake Engineering Society of Korea
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    • v.7 no.6
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    • pp.101-108
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    • 2003
  • Small-scale models have been frequently used for experimental evaluation of seismic performance because of limited testing facilities and economic reasons. However, there are not enough studies on similitude law for analogizing prototype structures accurately with small-scale models, although conventional similitude law based on geometry is not well consistent in the inelastic seismic behavior. When fabricating prototype and small-scale model of reinforced concrete structures by using the same material. added mass is demanded from a volumetric change and scale factor could be limited due to size of aggregate. Therefore, it is desirable that different material is used for small-scale models. Thus, a modified similitude law could be derived depending on geometric scale factor and equivalent modulus ratio. In this study, compressive strength tests are conducted to analyze equivalent modulus ratio of micro-concrete to normal-concrete. Equivalent modulus ratios are divided into multi phases, which are based on ultimate strain level. Therefore, an algorithm adaptable to the pseudodynamic test. considering equivalent multi-phase similitude law based on seismic damage levels, is developed. In addition, prior to the experiment. it is verified numerically if the algorithm is applicable to the pseudodynamic test.

The Pseudo-Dynamic Test for the Seismic Retrofit System Utilizing Existing Bridge Bearings (교량의 기존 받침을 활용하는 내진보강시스템의 유사동적 실험)

  • Kwahk, Im-Jong;Cho, Chang-Beck;Kim, Young-Jin;Kwark, Jong-Won
    • Journal of the Earthquake Engineering Society of Korea
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    • v.11 no.1
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    • pp.21-27
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    • 2007
  • In this study, an approach that installs seismic isolation bearings was proposed for the seismic retrofit of the existing bridges. The method that replaces all existing bearings with seismic isolators was proposed already. However, in this study, we recommend to utilize the existing bearings for the benefit of safety and cost. According to our proposal, the seismic isolators do not support vertical loads but they Just function as the period shifter and the horizontal damper. To verify this approach experimentally, the real scale bearings and lead rubber bearings far the real highway bridges were designed and fabricated. And the responses of this isolated bridges to the assumed earthquakes were determined by the pseudo dynamic test scheme. The test results were also compared to the responses computed by the well known structural analysis software to check the reliability of the test. From the test results, we found that the retrofitted bridges using the proposed method showed stable performances under earthquakes.

Comparative Between Naive Bayes Classifier and Cosine Similarity Coefficient in Dynamic Document Filtering (동적인 문서 여과에서 나이브 베이즈 분류기와 코사인 유사 계수의 성능 비교)

  • Son Ki-Jun;Lim Soo-Yeoun;Park Seong-Bae;Lee Sang-Jo
    • Proceedings of the Korean Information Science Society Conference
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    • pp.214-216
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    • 2006
  • 온라인 정보가 증가함에 따라 많은 양의 정보 중에서 사용자가 원하는 정보를 정확하고 신속하게 찾아 주는 문서 여과의 중요성 또한 증가하고 있는 추세이다. 본 논문은 문서 여과 문제를 이진 문서 분류 문제로 보고, 나이브 베이즈 분류기를 동적인 문서 여과 목적으로 사용하였다. 이때 사용자가 자신의 관심 분야에 해당하는 주제를 제대로 여과 받기 위해서 학습 대상으로 삼아야 할 학습문서의 범위와 관련성 있는 문서를 제대로 여과 받기 위해서 체크해야 하는 관련성 표기 비율에 따른 분류기의 성능에 대하여 실험을 하였다. 코사인 유사계수를 이용한 여과 방법과의 성능도 비교 실험하였다. 실험 결과 나이브 베이즈 이진 분류기는 문서집합의 크기가 일정한 정도일 때 관련성 있는 문서가 모두 표기되지 않더라도 여과에는 큰 영향을 미치지 않음을 볼 수 있었다.

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Pseudo Dynamic Test Study on Seismic Performance Evaluation of RC Columns Retrofitted by PolyUrea (내진보강용 폴리우레아로 보강된 철근콘크리트 기둥의 내진성능 평가에 대한 유사동적실험 연구)

  • Cho, Chul Min;Lee, Doo Sung;Kim, Tae Kyun;Kim, Jang-Ho Jay
    • Journal of The Korean Society of Civil Engineers
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    • v.37 no.2
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    • pp.289-301
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    • 2017
  • As earthquakes have frequently happened all over the world, huge losses of human life and property have occurred. Therefore, retrofitting and strengthen technologies of non-seismically designed structures in Korea are urgent. Also, there has been a growing interest about seismic retrofitting, where researches on the topic have been actively pursued in Korea. The study results showed that ductility inducing retrofitting method is more superior stiffness inducing method. In Japan, Super Reinforcement with Flexibility (SRF) was introduced. Therefore, in this study, seismic performance evaluation was performed through pseudo dynamic test and uniaxial compression test for RC column retrofitted by PolyUrea for ductility inducing retrofitting material. Uniaxial compression test results showed that strength of all specimens retrofitted by PolyUrea was higher than that of RC specimens. Also, all specimens retrofitted by PolyUrea also showed ductile fracture behavior. In pseudo dynamic test, by appling real earthquake record, the seismic behavior of RC column reinforced by PolyUrea was evaluated through relative displacement, reinforcement strain, displacement ductility, and dissipation energy. The results showed that PolyUrea helped to enhance seismic performance of RC columns.

Assessment of the Sorption Characteristics of Cadmium onto Steel-making Slag in Simulated Sea Water Using Batch Experiment (모사해수 조건에서 회분식 실험을 이용한 제강슬래그의 카드뮴 흡착 특성 평가)

  • Kim, Eun-Hyup;Rhee, Sung-Su;Lee, Gwang-Hun;Kim, Yong-Woo;Park, Jun-Boum;Oh, Myoung-Hak
    • Journal of the Korean Geotechnical Society
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    • v.27 no.4
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    • pp.43-50
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    • 2011
  • Steel-making slag was investigated as reactive material for removal of cadmium in coastal area. Batch experiments of the sorption isotherm experiment and kinetic sorption experiment were performed. Result of sorption isotherm was more adequately described by Langmuir model than Freundlich model and theoretical maximum capacity (${\beta}$) of cadmium onto steel-making slag was found. Results of kinetic sorption experiments were evaluated by pseudo second order model to investigate sorption characteristics of cadmium onto steel-making slag. Results showed that the equilibrium sorption amount of cadmium (q$q_e$) increased and the rate constant ($k_2$) and initial sorption rate (h) decreased as the initial cadmium concentration increased. The $q_e$ with simulated sea water was similar to that with deionized water and $k_2$ and h with simulated sea water was lower than those with deionized water. Results of kinetic experiments could be used to predict the result from sorption isotherm, since equilibrium sorption amounts calculated by pseudo second order model generally agreed with those measured from sorption isotherm. The reaction time for the target removal rate could be calculated by the pseudo second order model using kinetic sorption tests results.

Seismic Performance Evaluation of Medium-and Low-rise R/C Buildings Strengthened with RCSF External Connection Method by Pseudo Dynamic Test (유사동적실험에 의한 RCSF 외부접합공법으로 내진보강 된 중·저층 철근콘크리트 건물의 내진성능 평가)

  • Lee, Kang-Seok
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.1
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    • pp.13-22
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    • 2015
  • In this study, a new RCSF (Reinforced Concrete Steel Frame) external connection method is proposed for seismic strengthening of medium-and low-rise reinforced concrete buildings. The RCSF method, proposed in this study, is capable of carrying out the seismic retrofitting construction while residents can live inside structures. The method is one of the strength design approach by retrofit which can easily increase the ultimate lateral load capacity of concrete buildings controlled by shear. The pseudo-dynamic test, designed using a existing school building in Korea, was carried out in order to verify the seismic strengthening effects of the proposed method in terms of the maximum load carrying capacity and ductility. Test results revealed that the proposed RCSF strengthening method installed in RC frame enhanced conspicuously the strength and displacement capacities, and the method can resist markedly under the large scaled earthquake intensity level.

Seismic Performance Evaluation of RC Bridge Piers with Limited Ductility by the Pseudo-Dynamic Test (한정연성 철근콘크리트 교각의 유사동적 실험에 의한 내진 성능 평가)

  • Chung, Young-Soo;Park, Chang-Kyu;Park, Jin-Young
    • Journal of the Korea Concrete Institute
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    • v.15 no.5
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    • pp.705-714
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    • 2003
  • Even though Korean peninsula is located in regions of moderate seismic risks, current seismic design provisions of the roadway bridge design code have adopted the AASHTO code which is based on the requirements for high seismic regions. The objective of this research is to investigate the seismic performance of circular reinforced concrete (RC) bridge piers with limited ductility, which may be desirable in low or moderate seismic regions, such as in Korea. Four test specimens were designed and constructed. The reference specimen was designed with longitudinal steel ratio as 1.01% and the confinement reinforcement ratio as 0.13% without considering earthquake, and three other test specimens were designed in accordance with a limited-ductility concept as 0.3% for the confinement steel ratio. This confinement ratio is 0.32 times of minimum lateral reinforcement specified in current seismic design provisions, and 2.3 times of lateral reinforcement required in nonseismic design provisions. The pseudo-dynamic test was carried out to evaluate the seismic performance of full-scale specimens in size of 1.2m diameter and 4.8m height. Judging from the experiment, the reference specimen was not satisfactory for the demand displacement ductility ${\mu}$=5.0, but three limited-ductility specimens appeared to have the displacement ductility of more than 5.

Purchase Transaction Similarity Measure Considering Product Taxonomy (상품 분류 체계를 고려한 구매이력 유사도 측정 기법)

  • Yang, Yu-Jeong;Lee, Ki Yong
    • KIPS Transactions on Software and Data Engineering
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    • v.8 no.9
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    • pp.363-372
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    • 2019
  • A sequence refers to data in which the order exists on the two items, and purchase transaction data in which the products purchased by one customer are listed is one of the representative sequence data. In general, all goods have a product taxonomy, such as category/ sub-category/ sub-sub category, and if they are similar to each other, they are classified into the same category according to their characteristics. Therefore, in this paper, we not only consider the purchase order of products to compare two purchase transaction sequences, but also calculate their similarity by giving a higher score if they are in the same category in spite of their difference. Especially, in order to choose the best similarity measure that directly affects the calculation performance of the purchase transaction sequences, we have compared the performance of three representative similarity measures, the Levenshtein distance, dynamic time warping distance, and the Needleman-Wunsch similarity. We have extended the existing methods to take into account the product taxonomy. For conventional similarity measures, the comparison of goods in two sequences is calculated by simply assigning a value of 0 or 1 according to whether or not the product is matched. However, the proposed method is subdivided to have a value between 0 and 1 using the product taxonomy tree to give a different degree of relevance between the two products, even if they are different products. Through experiments, we have confirmed that the proposed method was measured the similarity more accurately than the previous method. Furthermore, we have confirmed that dynamic time warping distance was the most suitable measure because it considered the degree of association of the product in the sequence and showed good performance for two sequences with different lengths.