• Journal of the Korea Computer Industry Society
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• v.5 no.5
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• pp.755-760
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• 2004

In this paper, an advanced successive elimination algorithm was proposed using mean absolute difference of neighboring search points. By using mean absolute difference of neighboring search points, the search point in motion estimation can be eliminated effeciently without matching evaluation that requires very intensive computations. By using adaptive MAD calculation algorithm, the candidate matching block can be eliminated early. So, the number of the proposed algrorithm was verified by experimental results.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.6
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• pp.669-678
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• 2009

Real-time image georeferencing technologies are required to generate spatial information promptly from the image sequences acquired by a multi-sensor system. We thus derive a sequential adjustment algorithm based on the combined adjustment model. By adopting the sequential adjustment model, we develop a sequential AT(Aerial Triangulation) algorithm to georeference image sequences in real-time. The proposed algorithm enables to perform AT rapidly with the minimum computation at the current stage by using the results computed at the previous stage whenever a new image is added. Experiments with simulated data were conducted to verify the effectiveness of the proposed algorithm. The results of the experiments show that the georeferencing of each image took very short time and its accuracy was determined within ${\pm}4cm$ on the ground control points comparing to the results of the existing simultaneous AT.

• Journal of the Korean Society for Railway
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• v.14 no.2
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• pp.116-120
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• 2011

For the train positioning system currently applied in high-speed MAGLEV train systems, it is classified into absolute positioning systems which discontinuously detect train positions, and relative positioning systems which continuously detect train positions. In this paper we analyze the configuration model and the numerical model of the absolute positioning system applied in TRANSRAPID which is a representative high-speed MAGLEV train, and design the two configuration models specific to the recognition structures of absolute positioning systems. We also verify the compatibility of the design models of absolute positioning system through simulation using MATLAB and propose the optimal configuration model of absolute positioning systems for high-speed MAGLEV train system.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.4
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• pp.251-258
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• 2024

This study investigated the effect of bearing aging on the seismic response of a three-span continuous concrete girder bridge with pot bearings installed. The pot bearings were modeled as elastic springs in the longitudinal, transverse, and vertical directions of the bridge to reflect the stiffness of fixed and movable supports. The effect of bearing aging on the seismic response of the bridge was examined by considering two factors: a decrease in the horizontal stiffness of the fixed bearings and an increase in the horizontal stiffness of the movable bearings. The finite element model of the three-span continuous girder bridge was validated by comparing its numerical natural frequencies with the designed natural frequencies. Using artificial ground motions that conform to the design response spectrum specified by the KDS bridge seismic design code, the seismic responses of the bridge's girders and bearings were calculated, considering the bearing stiffness variation due to aging. The results of a numerical analysis revealed that a decrease in the horizontal stiffness of the fixed bearings led to an increase in the absolute maximum relative displacement of the bearings during an earthquake. This increases the risk of the mortar block that supports the bearing cracking and the anchor bolt breaking. However, an increase in the horizontal stiffness of the movable bearings due to aging decreased the absolute maximum shear on the fixed bearings. Despite the shear reduction in the fixed bearings, the aging of the pot bearings change could cause additional tensile bending stress in the girder section above the free bearings, which could lead to unexpected structural damage to the continuous bridge during an earthquake.

• The Korean Journal of Applied Statistics
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• v.26 no.3
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• pp.549-568
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• 2013

This paper discusses conversion methods between multiple decrement models and associated single decrement models. One of most popular assumptions on fractional age is UDD(uniform distribution of decrement) or constant force of mortality in actuarial practice. Instead of these assumptions, this paper suggests cubic spline interpolation to approximate the distribution of fractional age with the continuous force of decrements. Conversion formulas are derived. The comparisons of these two methods based on the numerical data show that the cubic spline interpolation approach is more accurate.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.3
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• pp.68-75
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• 1999

본 논문은 항공영상으로부터 REM( recovered elevation map)를 추출하여 DEM (digital elevation model)과 정합함으로써 비행체의 위치를 추정하는 기법을 제안하였다. 제안한 알고리듬은 연속항공영상을 이용함으로써 보다 넓은 지역에 대한 REM (recovered elevation map)복원이 가능하여 정합확률이 높아진다. 또한 강건한 거리 척도를 사용함으로써 몇 개의 점에서의 매우 큰 오차에 영향을 받지 않은 알고리듬을 제안하였다. 본 논문에선 몇 개의 항공영상을 가지고 컴퓨터 시뮬레이션을 통하여 제안한 알고리듬의 효용성을 보였다.

• Communications for Statistical Applications and Methods
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• v.4 no.2
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• pp.549-556
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• 1997

본 논문에서는 Block과 Basu (1974)가 제안한 절대연속이변량지수분포(absolutely continuous bivariate exponential distribution : ACBVED)의 독립성검정에 대한 Score검정과 이 검정의 점근성을 높이기 위하여 Cordeiro와 Ferrari (1991)가 제시한 Bartlett수정항과 유사한 형태의 수정된 Score검정을 유도하였다. 그리고 수정된 Score검정의 점근성의 효과와 주변분포가 동일하다는 가정하에서 Gupta, Mehrotra와 Michalek (1984)가 제안한 우도비검정을 모의실험으로 비교하였다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.2
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• pp.123-129
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• 2016

Recently indoor positioning technologies have been studied using the acoustic signal from a smart phone. Also multi-hop indoor positioning system in which the equipments measure their relative position successively has been proposed. As the total positioning error is prone to increase due to the successively accumulated positioning error for the multi-hop system, the error analysis is required for the system design. In this paper, the absolute positioning error for the multi-hop indoor positioning equipments successively installed is analyzed, and it is verified by computer simulation. According to the results, the accumulated positioning error is linearly increased as the number of the multi-hop increases.

• Geotechnical Engineering
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• v.14 no.4
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• pp.17-32
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• 1998

has been much progress in theories and construction techniques to secure the stability of the underground structures. Recently, several studios have shown that it is possible to predict the existence of discontinuities ahead of a tunnel face by analyzing 3-dimensional absolute displacements measured during tunnel excavation. This paper concentrated on the development of a methodology to predict the existence and location of the discontinuities, or the void space(abandoned mine) , by performing 3-dimensional FEM analysis and considering the stress relocation caused by arching effect during excavation. Also, this study tried to verify deformation for choosing the most suitable support system. The results of this study might provide a way of safer and economical tunnel construction by utilizing the in-situ monitoring data.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.5
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• pp.453-463
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• 2001

This paper presents an absolute position estimation method using Indian remote sensing (IRS) satellite images, which is a part of a position estimation (PE) system. The accumulated buffer (AB) matching method is proposed, in which a set of accumulator cells is employed for fast edge-based matching. By computer simulations with two sets of veal aerial image sequences, the performance of the AB matching method is analyzed and its effectiveness is shown in terms of the position error in the hybrid PE system.