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        검색결과 25

        21.
        2017.04 서비스 종료(열람 제한)
        For the evaluation of load carrying capacity of continuous bridges, the testing target span should be selected where peak impact factor can be expected. In this paper, two and three continuous bridges with equal span length are considered and the moving vehicle load analysis is performed. All possible vehicle speeds are applied to the bridges and the peak impact factors obtained for each span are investigated. From the results, the maximum peak impact factors are developed at the middle of the first span to the direction of vehicle moving.
        22.
        2015.04 서비스 종료(열람 제한)
        This paper presents a laboratory validation for a Finite Element model updating method using moving vehicle input-deflection output measurements. In conventional FE model updating, a few natural frequencies measured from field experiments have been used to update the FE model based on the assumption that the mass matrix is known accurately. The proposed approach can update the stiffness matrix without the assumption by using static input-output measurements and can even update the mass matrix by using a few natural frequencies obtained from dynamic measurements. Laboratory experiments were carried out for a scaled model of Samseung Bridge located in the test road of Korea Highway Corporation. For a simplicity of experiments, a mass (11kgf) was located in four different locations on the deck and two deflections were measured by laser displacement meters: one at the center girder, and the other in at the outer girder, both in mid-span. Results showed that the proposed methods was capable to estimate Young's Modulus and the mass density of the model bridge accurately while natural-frequency-based updating may result in significant error when higher modes (2nd, 3rd) were used.
        23.
        2013.12 KCI 등재 서비스 종료(열람 제한)
        Most of livestock houses are concentrated in certain area with mass rearing system resulting in rapid spread of infectious diseases such as HPAI (highly pathogenic avian influenza). The livestock-related vehicles which frequently travel between farms could be a major factor for disease spread by means of transmission of airborne aerosol including pathogens. This study was focused on the quantitative measurement of aerosol concentration by field experiment while vehicles were passing through the road. The TSP (total suspended particle) and PM10 (particle matter) were measured using air sampler with teflon filter installed downward the road with consideration of weather forecast and the direction of road. And aerosol spectrometer and video recorders were also used to measure the real-time distribution of aerosol concentration by its size. The results showed that PM2.5 was not considerable for transmission of airborne aerosol from the livestock-related vehicle. The mass generated from the road during the vehicle movement was measured and calculated to 241.4 μg/m3 by means of the difference between TSP and PM2.5. The dispersion distance was predicted by 79.6 m from the trend curve.
        24.
        2012.11 서비스 종료(열람 제한)
        The slope adjacent to the road, when it is difficult to observe the shape and if not at the bottom of the upper slopes or steep high due to the presence of the upper slopes of the exact visual inspection is difficult, there is a direct investigation lengthy complaints. In this study, the disadvantages of having the inspection personnel based complementary and mixed low-cost single global region is the number of slope maintenance and safety can be managed efficiently so that helicopters and hexa mobile survey vehicle was developed. Equipment developed difficulties in spatial or temporal slope Visually inspect efficient investigation to be able to support. Survey vehicle computer to the Internet environment because it contains Slope check immediately to determine test results sent to the Center, and the efficient maintenance can be performed.
        25.
        2008.03 KCI 등재 서비스 종료(열람 제한)
        Recently, automatic parking assist systems are commercially available in some cars. In order to improve the reliability and the accuracy of parking control, pose uncertainty of a vehicle and some experimental issues should be solved. In this paper, following three schemes are proposed. (1) Odometry calibration scheme for the Car-Like Mobile Robot.(CLMR) (2) Accurate localization using Extended Kalman Filter(EKF) based redundant odometry fusion. (3) Trajectory tracking controller to compensate the tracking error of the CLMR. The proposed schemes are experimentally verified using a miniature Car-Like Mobile Robot. This paper shows that odometry accuracy and trajectory tracking performance can be dramatically improved by using the proposed schemes.
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