• Structural Engineering and Mechanics
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• 제71권4호
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• pp.377-390
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• 2019

A method for estimating the floor response spectra (FRS) of elastic structures under earthquake excitations is proposed. The method is established based on a previously proposed direct estimation method for single degree of freedom systems, which generally overestimates the FRS of a structure, particularly in the resonance period range. A modification factor is introduced to modify the original method; the modification factor is expressed as a function of the period ratio and is determined through regression analysis on time history analysis results. Both real and artificial ground motions are considered in the analysis, and it is found that the modification factors obtained from the real and artificial ground motions are significantly different. This suggests that the effect of ground motion should be considered in the estimation of FRS. The modified FRS estimation method is further applied to a 10-story building structure, and it is verified that the proposed method can lead to a good estimation of FRS of multi-story buildings.

• International Journal of Precision Engineering and Manufacturing
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• 제8권4호
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• pp.27-32
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• 2007

Gears, crucial components in modern precision machinery for power transmission mechanisms, are required to have low contacting noise with high torque transmission, which makes the use of gear-tooth profile modifications and gear-tooth surface crowning extremely efficient and valuable. Due to the shortcomings of current techniques, such as manual rectification, mechanical modification, and numerically controlled rectification, we propose a novel electrochemical gear-tooth profile modification method based on an artificial neural network control technique. The fundamentals of electrochemical tooth-profile modifications based on real-time control and a mathematical model of the process are discussed in detail. Due to the complex and uncertain relationships among the machining parameters of electrochemical tooth-profile modification processes, we used an artificial neural network to determine the required processing electric current as the tooth-profile modification requirements were supplied. The system was implemented and a practical example was used to demonstrate that this technology is feasible and has potential applications in the production of precision machinery.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2005년도 학술발표회 논문집
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• pp.372-379
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• 2005

The earthquake resistant design concept allows the nonlinear behavior of structures under the design earthquake. Therefore the response spectrum method provided in most codes introduces the response modification factors to consider the nonlinear behavior in the design process. For bridges, the response modification factors are given according to the ductility as well as the redundancy of piers. In this study, among influence factors on the nonlinear seismic behavior, the randomness of artificial accelerograms simulated with different durations, the pier ductility represented by the inelastic behavior characteristic curve and the regularity represented by pier heights are selected. The influence of such factor on the seismic behavior is investigated by comparing response modification factors calculated with the nonlinear time step analysis.

• 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.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 1994년도 춘계연구발표회 논문개요집
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• pp.30-31
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• 1994

• 한국정보교육학회:학술대회논문집
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• 한국정보교육학회 2021년도 학술논문집
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• pp.149-157
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• 2021

2022년 개정 교육과정에 인공지능 교육 도입을 앞두고 인공지능을 학습 소재로 한 다양한 수업들이 개발되어야 하는 시점이다. 본 연구에서는 설계기반연구를 활용하여 설명가능한 인공지능을 기반한 인공지능 교육 프로그램을 개발하였다. 인공지능의 기초, 활용, 윤리 세 분야를 골고루 포괄하며 실생활 사례와도 쉽게 연결시킬 수 있는 설명가능한 인공지능을 핵심 주제로 설정하였다. 일반적인 설계기반연구(Design-based research, DBR)에서는 3차 이상의 반복적인 과정이 이루어지지만 본 연구 결과는 1차 설계, 적용 및 평가에 대한 결과를 바탕으로 연구가 진행되었다. 추후 학교 현장에 적용하여 3차 수정 및 보완을 바탕으로 더욱 완성된 설명가능한 인공지능을 주제로 한 프로그램을 개발하고자 한다. 본 연구가 학교 현장에 도입되는 인공지능 교육의 발전에 도움이 되기를 기대한다.

• Journal of Information Processing Systems
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• 제14권2호
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• pp.448-454
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• 2018

Artificial bee colony (ABC) algorithm has attracted significant interests recently for solving the multivariate optimization problem. However, it still faces insufficiency of slow convergence speed and poor local search ability. Therefore, in this paper, a modified ABC algorithm with bees' number reallocation and new search equation is proposed to tackle this drawback. In particular, to enhance solution accuracy, more bees in the population are assigned to execute local searches around food sources. Moreover, elite vectors are adopted to guide the bees, with which the algorithm could converge to the potential global optimal position rapidly. A series of classical benchmark functions for frequency-modulated sound waves are adopted to validate the performance of the modified ABC algorithm. Experimental results are provided to show the significant performance improvement of our proposed algorithm over the traditional version.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1998년도 Proceedings of International Workshop on Advanced Image Technology
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• pp.99-104
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• 1998

Application sharing is the ability to use existing applications, such as Excel or MS-Word, during a group session without modification. In this paper, we present the design and implementation of an application sharing system, called ShareIt, which enable users to share arbitrary MS-Windows applications under the Win 3.1/95/NT and X window system, and evaluation of the system performance. To share an application, the image of the application window is captured and transmitted to other sites. With the use of the window capturing method, ShareIt allows any MS-Windows application to be shared regardless of not only the window systems but also the version-up of window systems.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1999년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.61-68
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• 1999

In the nonlinear dynamic structural analysis the given ground excitation as an input should be well defined. Because of the lack of recorded accelerograms in Korea it is required to generate an artificial earthquake by a stochastic model of ground excitation with various dynamic properties rather than recorded accelerograms. It is well known that earthquake motions are generally non-stationary with time-varying intensity and frequency content. Many researchers have proposed non-stationary random process models. Yeh and Wen (1990) proposed a non-stationary modulation function and a power spectral density function to describe such non-stationary characteristics. Satio and Wen(1994) proposed a non-stationary stochastic process model to generate earthquake ground motions which are compatible with design reponse spectrum at sites in Japan. this paper shows the process to modify power spectrum compatible with target design response spectrum for generating of nonstationary artificial earthquake ground motions. Target reponse spectrum is chosen by ATC14 to calibrate the response spectrum according to a give recurrence period.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.280-280
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• 2013

In green plants, energy generation is accomplished through light-harvesting photosystem, which utilize abundant visible light and multi-stepwise redox reaction to oxidize water and reduce NADP+, transferring electrons efficiently with active cofactors1. Inspired by natural photosynthesis, artificial solar water-splitting devices are being designed variously. However, the several approaches involving immobilization2, conjugation3, and surface modification4 still have limitations. We have made artificial photosynthesis templates by self-assembling tyrosine-based peptide to mimick photosystem II. Porphyrin sensitizer absorbing blue light strongly was conjugated with the templates and they were hybridized with cobalt oxide through the reduction of cobalt ions in an aqueous solution. The formation of hybrid templates was characterized using TEM, and their water oxidation performance was measured by fluorescence oxygen probe. Our results suggest that the bio-templated assembly of functional compounds has a great potential for artificial photosynthesis.