• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(II)
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• pp.1059-1064
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• 2002

The behavior of an opening and the performance of support system depend upon the load-deformation characteristics of ground and support as well as of the manner and of timing of support installation. The load-deformation characteristics of ground and support are derived by the interaction between ground and support. The interaction between ground and support is qualitatively illustrated by a ground response curve. The behavior of an opening and the performance of support system depend upon the load-deformation characteristics of ground and support as well as of the manner and of timing of support installation. The interaction between ground and support is qualitatively illustrated by a ground response curve. The convergence-confinement method don't need the basic assumptions for a mathematical model. Also This is applicable to general tunnel. Consequently the stability of tunnel must be qualitatively investigated by a ground response curve and quantitatively adjudged by a numerical analysis for the reasonable design of tunnel.

• Nuclear Engineering and Technology
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• 제51권1호
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• pp.293-302
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• 2019

Many researches have been done to develop and improve the performance of personal (individual) dosimeter response to cover a wide of neutron energy range (from thermal to fast). Depending on the individual category of the dosimeter, the semiconductor sensor has been used to simplify and lightweight. In this plan, it's very important to have a fairly accurate counting of doses rate in different energies. With a general design and single-sensor simulations, all optimal thicknesses have been extracted. The performance of the simulation scheme has been compared with the commercial and laboratory samples in the world. Due to the deviation of all dosimeters with a flat energy response, in this paper, has been used an idea of one semi-conductor sensor to have the flat energy-response in the entire neutron energy range. Finally, by analyzing of the sensors data as arrays for the first time, we have reached a nearly flat and acceptable energy-response. Also a comparison has been made between Lucite-PMMA ($H_5C_5O_2$) and polyethylene-PE ($CH_2$) as a radiator and $B_4C$ has been studied as absorbent. Moreover, in this paper, the effect of gamma dose in the dosimeter has been investigated and shown around the standard has not been exceeded.

• 국제초고층학회논문집
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• 제1권3호
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• pp.181-194
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• 2012

Chile is characterized by the largest seismicity in the world which produces strong earthquakes every $83{\pm}9years$ in the Central part of Chile, where it is located Santiago, the capital of Chile. The short interval between large earthquakes magnitude 8.5 has conditioned the Chilean seismic design practice to achieve almost operational performance level, despite the fact that the Chilean Code declares a scope of life safe performance level. Several Indexes have been widely used throughout the years in Chile to evaluate the structural characteristics of concrete buildings, with the intent to find a correlation between general structural conception and successful seismic performance. The Indexes presented are related only to global response of buildings under earthquake loads and not to the behavior or design of individual elements. A correlation between displacement demand and seismic structural damage is presented, using the index $H_o/T$ and the concrete compressive strain ${\varepsilon}_c$. Also the Chilean seismic design codes pre and post 2010 Maule earthquake are reviewed and the practice in seismic design vs Performance Based Design is presented. Performance Based Design procedures are not included in the Chilean seismic design code for buildings, nevertheless the earthquake experience has shown that the response of the Chilean buildings has been close to operational. This can be attributed to the fact that the drift of most engineered buildings designed in accordance with the Chilean practice falls below 0.5%. It is also known by experience that for frequent and even occasional earthquakes, buildings responded elastically and thus with "fully operational" performance. Taking the above into account, it can be said that, although the "basic objective" of the Chilean code is similar to the SEAOC VISION2000 criteria, the actual performance for normal buildings is closer to the "Essential/Hazardous objective".

• Earthquakes and Structures
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• 제14권6호
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• pp.537-549
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• 2018

Using vertical links in eccentric braced frames is one of the best passive structural control approaches due to its effectiveness and practicality advantages. However, in spite of the subject importance there are limited studies which evaluate the seismic reliability and response reduction factor (R-factor) in this system. Therefore, the present study has been conducted to improve the current understanding about failure mechanism in the structural systems equipped with vertical links. For this purpose, following definition of demand and capacity response reduction factors, these parameters are computed for three different buildings (4, 8 and 12 stories) equipped with this system. In this regards, pushover and incremental dynamic analysis have been employed, and seismic reliability as well as multi-level response reduction factor according to the seismic demand and capacity of the frames have been derived. Based on the results, this system demonstrates high ductility and seismic energy dissipation capacity, and using the response reduction factor as high as 8 also provides acceptable reliability for the frame in the moderate and high earthquake intensities. This system can be used in original buildings as lateral load resisting system in addition to seismic rehabilitation of the existing buildings.

• 한국초등과학교육학회지:초등과학교육
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• 제24권1호
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• pp.30-42
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• 2005

In this study, we developed an elementary science performance assessment material on STS theme, especially the respiration. The material is constituted with 3 components, which are performance task, students' response format and scoring system, and it also has various objective domains such as applying science knowledge, improving science attitude, using ICT, communicating and reflective thinking. It offers teachers a tool by which they can assess students' abilities on a whole. The task is made with the motivation-evoking content of 'No Smoking'. It is constructed on the activity of writing a letter to his/her father not to smoke. The students' response format is made by problem solving process, and the scoring system is matched with the steps of students' response. The material involves several theoretical backgrounds and the strengths of performance assessment. In addition, due to the detailed students' format and scoring system, it can be used practically in elementary science classroom.

• 한국소음진동공학회논문집
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• 제22권7호
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• pp.650-658
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• 2012

This paper proposes a high performance position controller for a driving system using a time optimal controller which has been widely used to control driving systems to achieve desired reference position or velocity in a minimum response time. The main purpose of this research lies in an improvement of transient response performance rather than that of steady-state response in comparison with other control strategies. In order to refine the scheme of time optimal control, Lyapunov stability proofs are incorporated in a controller of standard second order system model. This scheme is applied to the control of a driving system. In view of the simulation and experiment results, the standard second order system model exhibits better minimum-time control performance and robustness than double integral system model does.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 추계 학술논문 발표대회
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• pp.134-136
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• 2013

In general, the seismic retrofit is almost essential to extend and remodel aged buildings. Because domestic seismic design code has been enhanced, seismic performance should be secure for aged building remodeling. Seismic response reduction device (damper) is lately appling to ensure seismic performance. This device is economical efficiency method that can reduce the load to foundation and the range of structural reinforcements, shorten of construction period. New shaped steel damper was applied for extension and remodeling construction for Boramae Deakyo building. As a result, the economy and shortening of construction period was achieved.

• Structural Engineering and Mechanics
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• 제56권4호
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• pp.549-567
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• 2015

A first-order moment method (FORM) reliability analysis is commonly used for structural stability analysis. It requires the values and partial derivatives of the performance to function with respect to the random variables for the design. These calculations can be cumbersome when the performance functions are implicit. A Gaussian process (GP)-based response surface is adopted in this study to approximate the limit state function. By using a trained GP model, a large number of values and partial derivatives of the performance functions can be obtained for conventional reliability analysis with a FORM, thereby reducing the number of stability analysis calculations. This dynamic renewed knowledge source can provide great assistance in improving the predictive capacity of GP during the iterative process, particularly from the view of machine learning. An iterative algorithm is therefore proposed to improve the precision of GP approximation around the design point by constantly adding new design points to the initial training set. Examples are provided to illustrate the GP-based response surface for both structural and non-structural reliability analyses. The results show that the proposed approach is applicable to structural reliability analyses that involve implicit performance functions and structural response evaluations that entail time-consuming finite element analyses.

• Structural Engineering and Mechanics
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• 제83권3호
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• pp.401-413
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• 2022

The collapse of civil infrastructure due to natural disasters results in financial losses and many casualties. In particular, the recent increase in earthquake activities has highlighted on the importance of assessing the seismic performance and predicting the seismic risk of a structure. However, the nonlinear behavior of a structure and the uncertainty in ground motion complicate the accurate seismic response prediction of a structure. Artificial intelligence can overcome these limitations to reasonably predict the nonlinear behavior of structures. In this study, a deep learning-based algorithm was developed to estimate the time-history seismic response of bridge structures. The proposed deep neural network was trained using structural and ground motion parameters. The performance of the seismic response prediction algorithm showed the similar phase and magnitude to those of the time-history analysis in a single-degree-of-freedom system that exhibits nonlinear behavior as a main structural element. Then, the proposed algorithm was expanded to predict the seismic response and fragility prediction of a bridge system. The proposed deep neural network reasonably predicted the nonlinear seismic behavior of piers and bearings for approximately 93% and 87% of the test dataset, respectively. The results of the study also demonstrated that the proposed algorithm can be utilized to assess the seismic fragility of bridge components and system.

• Journal of Mechanical Science and Technology
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• 제14권10호
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• pp.1122-1130
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• 2000

Based on the value of the Lagrange multiplier and the degree of constraint activeness, a new update rule is proposed for penalty parameters of the ALM method. The theoretical exposition of this suggested update rule is presented by using the algorithmic interpretation and the geometric interpretation of the augmented Lagrangian. This interpretation shows that the penalty parameters can effect the performance of the ALM method. Also, it offers a lower limit on the penalty parameters that makes the augmented Lagrangian to be bounded. This lower limit forms the backbone of the proposed update rule. To investigate the numerical performance of the update rule, it is embedded in our ALM based dynamic response optimizer, and the optimizer is applied to solve six typical dynamic response optimization problems. Our optimization results are compared with those obtained by employing three conventional update rules used in the literature, which shows that the suggested update rule is more efficient and more stable than the conventional ones.