• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제25권4호
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• pp.149-161
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• 2021

This study proposes a methodology for mission/path planning of an unmanned aerial vehicle (UAV) using an artificial potential field with the Markov Decision Process (MDP). The planning problem is formulated as an MDP. A low-resolution solution of the MDP is obtained and used to define an artificial potential field, which provides a continuous UAV mission plan. A numerical case study is conducted to demonstrate the validity of the proposed technique.

• Nuclear Engineering and Technology
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• 제51권3호
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• pp.807-817
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• 2019

Airborne Gamma Ray Spectrometry (AGRS) with its important applications such as gathering radiation information of ground surface, geochemistry measuring of the abundance of Potassium, Thorium and Uranium in outer earth layer, environmental and nuclear site surveillance has a key role in the field of nuclear science and human life. The Broyden-Fletcher-Goldfarb-Shanno (BFGS), with its advanced numerical unconstrained nonlinear optimization in collaboration with Artificial Neural Networks (ANNs) provides a noteworthy opportunity for modern AGRS. In this study a new AGRS system empowered by ANN-BFGS has been proposed and evaluated on available empirical AGRS data. To that effect different architectures of adaptive ANN-BFGS were implemented for a sort of published experimental AGRS outputs. The selected approach among of various training methods, with its low iteration cost and nondiagonal scaling allocation is a new powerful algorithm for AGRS data due to its inherent stochastic properties. Experiments were performed by different architectures and trainings, the selected scheme achieved the smallest number of epochs, the minimum Mean Square Error (MSE) and the maximum performance in compare with different types of optimization strategies and algorithms. The proposed method is capable to be implemented on a cost effective and minimum electronic equipment to present its real-time process, which will let it to be used on board a light Unmanned Aerial Vehicle (UAV). The advanced adaptation properties and models of neural network, the training of stochastic process and its implementation on DSP outstands an affordable, reliable and low cost AGRS design. The main outcome of the study shows this method increases the quality of curvature information of AGRS data while cost of the algorithm is reduced in each iteration so the proposed ANN-BFGS is a trustworthy appropriate model for Gamma-ray data reconstruction and analysis based on advanced novel artificial intelligence systems.

• 한국정밀공학회지
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• 제26권11호
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• pp.77-84
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• 2009

Alignment error of the BGA lithography equipment is mainly caused by the dimensional change of the BGA panel which is generated during the manufacturing processes. To minimize the alignment error, 'mark alignment' algorithm in place of 'center alignment' algorithm was proposed and the optimal solution for the algorithm was derived by simple analytic form. The developed algorithm distributes evenly the alignment error over the whole panel which was evaluated by the numerical simulation. Finally, the developed algorithm was implemented to the controller of the lithography equipment and the alignment error was measured at the fiducial mark location. From the measurement, it is also concluded that the developed alignment algorithm be effective to reduce the maximum value of alignment error.

• 대한의용생체공학회:의공학회지
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• 제41권1호
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• pp.28-34
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• 2020

In this paper, we introduce motion artifact reduction algorithm for interleaved MRI using an advanced 3D approximation algorithm. The motion artifact framework of this paper is data corrected by post-processing with a new 3-D approximation algorithm which uses data structure for each voxel. In this study, we simulate and evaluate our algorithm using Shepp-Logan phantom and T1-MRI template for both scattered dataset and uniform dataset. We generated motion artifact using random generated motion parameters for the interleaved MRI. In simulation, we use image coregistration by SPM12 (https://www.fil.ion.ucl.ac.uk/spm/) to estimate the motion parameters. The motion artifact correction is done with using full dataset with estimated motion parameters, as well as use only one half of the full data which is the case when the half volume is corrupted by severe movement. We evaluate using numerical metrics and visualize error images.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1568-1572
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• 2004

This paper proposes a new online calibration algorithm for the array antenna system. As you know, the several previous calibration methods for the mutual coupling did not estimate but measure mutual coupling effect at the real or test-bed system directly. Therefore we suggest some idea to compensate the calibration errors due to mutual coupling effect and mismatch in cables and electronic modules without the off-line calibration. In this work, we can calibrate the array antenna system under the operation of the system using Independent Component Analysis(ICA). This is what is called an online calibration. As you know, the ICA method has permutation and scaling problems. However, we solve problems of the ICA method and apply it to the calibration of an array antenna. The method simultaneously estimates the DOA(Direction of Arrival) of the signals, and calibrates the array for that specific angle. The proposed algorithm is evaluated by computer simulation and its behavior is illustrated by a numerical example.

• 한국정밀공학회지
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• 제17권12호
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• pp.201-208
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• 2000

A numerical analysis algorithm for thermally loaded structures has been proposed and compared with the general free vibration approach to determine the characteristics of thermal load effects in vibration structures. The field of numerical inspection includes free vibration analysis, transient heat transfer analysis and thermal stress analysis. The key point of the analysis of thermally loaded structure is the method of parallel time integration between transient heat transfer and free vibration simultaneously. The results of the study demonstrate the computation of the specific total external force vector and stiffness matrix. The proposed analysis method can be applied to both heated and cooled structure vibration analysis.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 봄 학술발표회 논문집
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• pp.11-18
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• 2003

This paper proposes modified Lanczos vector superposition method for efficient dynamic analysis of structures. Proposed method is based on the modified Lanczos algorithm that generates stiffness-orthonormal Lanczos vectors. Proposed method has better computing efficiency than the conventional Lanczos vector superposition method in the analysis of multi-input-loaded structures. The efficiency of proposed method is verified through numerical examples. Comparison with other vector superposition methods is also presented through numerical examples.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1995년도 추계학술대회 학술발표 논문집
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• pp.71-77
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• 1995

In this paper are proposed robust iterative learning control(ILC) algorithms for both linear continuous time-invariant system and linear discrete-time system. In contrast to conventional methods, the proposed learning algorithms are constructed based on both time domain performance and iteration-domain performance. The convergence of the proposed learning algorithms is proved. Also, it is shown that the proposed method has robustness in the presence of external disturbances and the convergence accuracy can be improved. A numerical external disturbances and the convergence accuracy can be improved. A numerical example is provided to show the effectiveness of the proposed algorithm.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.837-839
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• 2003

Low spatial resolution remote sensing (RS) data (LSRD) are promising in agricultural monitoring activities due to their high temporal resolution, but under such a spatial resolution, mixing in a pixel is a common problem. In this study, a numerical experiment was conducted to explore a mixed pixel problem in agriculture using a combined RSsimulation model SWAP (Soil-Water-Atmosphere -Plant) and a Genetic Algorithm (GA) approach. Results of the experiments showed that it is highly possible to address the mixed pixel problem with LSRD.

• 복합신소재구조학회 논문집
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• 제1권2호
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• pp.51-58
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• 2010

본 연구는 차량 이동하중을 받는 손상된 콘크리트 슬래브교량의 강성저하를 규명하고, 복합신소재를 사용하여 보강 후 성능평가를 수행한다. 특히 마이크로 유전알고리즘에 의한 역해석에 기반하여 보강 전 후 각 요소에서의 강성변화를 수정된 2차변수 Gaussian 분포함수를 사용하여 정식화하였다. 본 연구에서 제안한 방법은 기존의 요소기반 접근 방식에 비하여 수치해석적인 관점에서 효율성을 갖는다. 개발한 알고리즘은 3차원 솔리드 요소를 사용하여 모델링한 교량의 동적 거동 시뮬레이션으로부터 계측한 데이터를 사전정보로 사용하여 검증하였다. 몇 가지 수치예제는 본 연구에서 개발한 방법이 실제교량과 수치모델간의 차이로 인한 오차 및 노이즈 등으로 인한 동적 계측치 오류 등이 고려되었음에도 강성분포 추정 및 성능 평가를 효율적으로 수행함을 보여준다.