• Nuclear Engineering and Technology
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• 제48권3호
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• pp.831-839
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• 2016

Seismic qualification by test is widely used as a way to show the integrity and functionality of equipment that is related to the overall safety of nuclear power plants. Another means of seismic qualification is by direct integration analysis. Both approaches require a series of time histories as an input. However, in most cases, the possibility of using real earthquake data is limited. Thus, artificial time histories are widely used instead. In many cases, however, response spectra are given. Thus, most of the artificial time histories are generated from the given response spectra. Obtaining the response spectrum from a given time history is straightforward. However, the procedure for generating artificial time histories from a given response spectrum is difficult and complex to understand. Thus, this paper presents a simple time-domain method for generating a time history from a given response spectrum; the method was shown to satisfy conditions derived from nuclear regulatory guidance.

• 대한토목학회논문집
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• 제36권1호
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• pp.1-11
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• 2016

현 국내 외의 설계기준들은 인공지진파에 의해 계산된 응답스펙트럼이 설계응답스펙트럼보다 작은 값의 수가 5개 이내일 경우 설계응답스펙트럼을 포괄 한다고 규정하고 있다. 현 설계의 문제점을 확인하기 위하여 설계기준을 만족하는 5개의 각기 다른 특성을 가진 인공지진파를 사용하여 교각에 대한 시간이력해석을 수행하고, 부재력을 정량적으로 평가하였다. 설계기준을 만족하는 인공지진파일지라도 구조물의 고유주기와 유사한 주기에서 계산된 응답스펙트럼이 설계응답스펙트럼보다 작을 경우 시간이력해석을 통한 내진의 안전성을 확보하지 못함을 확인하였다. 따라서 본 연구에서는 스펙트럼 가속도 값이 설계응답스펙트럼보다 모든 주기에서 큰 값을 갖는 인공지진파를 생성하는 기법을 이중 수정함수를 적용하여 제안하였다. 또한 제안된 기법에 의해 작성된 인공지진파가 국내 외의 기준들의 적합성을 만족하는지 검토하였다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1998년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Spring 1998
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• pp.304-311
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• 1998

An algorithm to enhance spectra matching of acceleration time history used in the seismic analysis of nuclear power plants(NPP) is proposed. The new scheme provides the solution on the highly fluctuating and over conservatism problems that happened in order to satisfy design spectrum enveloping criteria in the traditional method. To obtain optimized spectrum for a time history, a spectrum matching procedure that adapts a system identification technique is also developed. The algorithm also introduces maximum displacement control, baseline correction, clipping and raising of maximum peak of time history, and power spectral density (PSD) control of time history. It is verified through numerical examples that this new scheme can definitely generate acceleration time history, closely matching the target spectra and satisfying other stipulated requirements.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.608-612
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• 2003

In the seismic response analysis, the artificial earthquake time history is generated to do the exact seismic analysis for the complex structural system like as containment building. In the present study the several simulated earthquakes are generated by use of SIMQKE program and the time history dynamic analysis of containment building is performed. Also, the seismic responses are statistically analyzed. The seismic response uncertainty arisen from the simulation of earthquakes is one of major uncertainties and the statistical description is needed to account for the random nature of earthquake.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 가을 학술발표회 논문집
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• pp.561-568
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• 2001

For obtaining the time history nodal responses of reactor building, a lumped-mass beam model composed of two sticks for the reactor building and the reactor support structure is developed. The time history responses for the non-isolated and isolated reactor buildings are calculated under an artificial time history, generated using the seismic spectrum curve of US NRC RG1.60. The analysis results show that the horizontal accelerations of the isolated building are dramatically decreased to one-tenths of the non-isolated one, but the vertical responses are increased by about 40%.

• Journal of information and communication convergence engineering
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• 제19권3호
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• pp.142-147
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• 2021

In this paper, we propose an intelligent research fund management system that applies artificial intelligence technology to an integrated research fund management system. By defining research fund management rules as work rules, a detection model learned using deep learning is designed, through which the disapproval status is presented for each research fund usage history. The disapproval detection system of the RCMS implemented in this study predicts whether the newly registered usage details are recognized or disapproved using an artificial intelligence model designed based on the use of an 8.87 million research fund registered in the RCMS. In addition, the item-detail recommendation system described herein presents the usage details according to the usage history item newly registered by the artificial intelligence model through a correlation between the research cost usage details and the item itself. The accuracy of the recommendation was shown to be 97.21%.

• 한국지진공학회논문집
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• 제12권5호
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• pp.31-38
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• 2008

최근 구조물의 지진해석에서 시간이력 지진해석의 필요성이 증대되고 있는데, 시간이력해석을 위해서는 최소7개의 지진기록을 사용하도록 IBC2003, ASCE와 KBC2005의 내진설계 기준에서 요구하고 있다. 시간이력 지진해석을 위해 지진기록의 선정은 주어진 대지 조건에 따른 설계스펙트럼을 만족하도록 시간이력 지진기록을 설계 지반조건과 유사한 지반에서 계측된 지진기록들 중에서 선정하거나 설계스펙트럼을 만족하는 인공지진기록을 생성하여 사용할 수 있지만, 이 연구에서는 절충적 방법으로 태평양지진연구센터(PEER) 데이터베이스에서 암반 지진기록으로 알려진 50개 계측지진기록을 이용하여 7개 인공 시간이력 지진기록을 생성하였다. 일차 조정계수를 곱한 지진응답스펙트럼이 목표설계스펙트럼에 최적합한 7개 지진기록을 선정하고, SRSS 평균값이 목표설계스펙트럼과 최소의 오차를 갖게 하는 최적합화법으로 구한 조정계수를 선정된 각 지진기록에 곱하여 7개 인공 시간이력 지진기록군을 생성하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.771-776
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• 2010

Since the importance of seismic design is greater, dynamic analysis is more widely using than past. The input motion is one of the most important factors of dynamic analysis. However, in Korea input motions are selected from U.S. and Japan those are captured from large magnitude earthquakes without considering seismic environment or generated in frequency domain. In this research, the methodology for generating input motions those are considered seismic environment and design code is proposed. The seismic environment compatibility is considered by performing deaggregation and the design code compatibility is considered by time-domain artificial time history accelration generation method. The results shows that seismic environment and design code compatible input motions are successfully generated.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2002년도 가을 학술발표회 논문집
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• pp.161-168
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• 2002

To evaluate seismic performance of bridges, two procedures far capacity spectrum method are presented. The capacity spectrum procedures include the reduction factor-ductility-period relationship in order to construct the inelastic demand spectra from the elastic demand spectra. Application of the procedures is illustrated by example analysis. Maximum displacements estimated by the procedures are compared to those by inelastic time history analysis for several artificial earthquakes. The results show that the maximum displacements estimated by the procedures are, on overall, smaller than those by the inelastic time history analysis

• Structural Engineering and Mechanics
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• 제22권2호
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• pp.185-195
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• 2006

Nowadays it is very necessary to generate artificial accelerograms because of lack of adequate earthquake records and vast usage of time-history dynamic analysis to calculate responses of structures. According to the lack of natural records, the best choice is to use proper artificial earthquake records for the specified design zone. These records should be generated in a way that would contain seismic properties of a vast area and therefore could be applied as design records. The main objective of this paper is to present a new method based on wavelet theory to generate more artificial earthquake records, which are compatible with target spectrum. Wavelets are able to decompose time series to several levels that each level covers a specific range of frequencies. If an accelerogram is transformed by Fourier transform to frequency domain, then wavelets are considered as a transform in time-scale domain which frequency has been changed to scale in the recent domain. Since wavelet theory separates each signal, it is able to generate so many artificial records having the same target spectrum.