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        검색결과 3

        1.
        2014.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: This study is to predict the Sound Pressure Level(SPL) obtained from the Noble Close ProXimity(NCPX) method by using the Extended Kalman Filter Algorithm employing the taylor series and Linear Regression Analysis based on the least square method. The objective of utilizing EKF Algorithm is to consider stochastically the effect of error because the Regression analysis is not the method for the statical approach. METHODS: For measuring the friction noise between the surface and vehicle’s tire, NCPX method was used. With NCPX method, SPL can be obtained using the frequency analysis such as Discrete Fourier Transform(DFT), Fast Fourier Transform(FFT) and Constant Percentage Bandwidth(CPB) Analysis. In this research, CPB analysis was only conducted for deriving A-weighted SPL from the sound power level in terms of frequencies. EKF Algorithm and Regression analysis were performed for estimating the SPL regarding the vehicle velocities. RESULTS : The study has shown that the results related to the coefficient of determination and RMSE from EKF Algorithm have been improved by comparing to Regression analysis. CONCLUSIONS : The more the vehicle is fast, the more the SPL must be high. But in the results of EKF Algorithm, SPLs are irregular. The reason of that is the EKF algorithm can be reflected by the error covariance from the measurements.
        4,000원
        2.
        2017.09 서비스 종료(열람 제한)
        Recently, as the awareness of safety has become more important, studies on damage assessment techniques for building structures have been actively conducted. The damage of the building structure is caused by the decrease of the stiffness which is inherent dynamic characteristic of the structural system, and the decrease of stiffness acts as a direct variable connected to the collapse of the structure. there have been developed techniques for estimating the inherent dynamics of a structure to identify and evaluate damage to the structure. In this study, we estimate the layer mass due to the modeling error through the optimization algorithm, Genetic Algorithm, and use the optimization algorithm GA to optimize the error covariance matrix, system noise and measured noise covariance matrix We propose an optimal state estimation algorithm. The objective function of the GA algorithm is obtained by the residual which is the difference between the measured values obtained from the EKF calculation and the values obtained from the system model. We verified the feasibility of the algorithm through a 4-DOF system.
        3.
        2012.07 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 자료동화기법의 하나인 확장 칼만 필터를 이용하여 유량자료의 실시간 품질향상을 수행하였다. 확장 칼만 필터의 상태-공간모형은 강우-유출모형과 관측유량자료를 이용하여 구성하였다. 본 연구에서는 실시간 품질향상 목적을 댐 유입량의 비정상적 고변동성 억제 및 관측유량의 결‧오측 보완으로 구분하였으며, 각각의 경우에 적절한 확장 칼만 필터 모형을 제시하였다. 이들 모형의 차이는 칼만이득 계산에 필요한 공분산 함수의 추정에 변동성만을 고려하는냐 또는 편의까지를 포함하느냐로 나타난다. 본 연구는 충주댐 유역을 대상으로 적용하였으며, 그 결과 제시된 모형들이 댐 유입량자료나 결‧오측이 포함된 유량자료의 실시간 품질향상에 효과적으로 작동함을 확인하였다.