論文 - 武居 周
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160億自由度数値人体モデルを用いた高周波電磁界解析の大規模可視化
杉本 振一郎, 高橋 一郎, 荻野 正雄, 武居 周
計算力学講演会講演論文集 2018 ( 0 ) 2018年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：一般社団法人 日本機械学会
This paper deals with a large-scale visualization of the numerical human body model. In order to treat a 16 billion degrees of freedom model, AVS/Express has been executed on the UV2000 of Information and Communications, Nagoya University. To reduce the load, the data necessary for visualization have been selected, and appropriate file formats have been chosen.
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武居 周
計算力学講演会講演論文集 2018 ( 0 ) 2018年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：一般社団法人 日本機械学会
In this research, we propose a microwave analysis method based on an iterative domain decomposition method. The simplified Berenger's PML is developed in which these eight corners are given the average value of all PML's layers. As for accuracy verification of the analysis solver, the absorbing performance of the PML is evaluated by using reflection coefficient based on S parameter. In the performance evaluation in high-frequency over 1 GHz, when the maximum side length is set to 1/20 of the wavelength, the error rate of between the numerical solution and the theoretical one is about serval percent using the PML of 8 layers. So, we have found that proposed method can calculate with high accuracy.
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Performance Evaluation of Numerical Current Analysis with Anatomical Human Model 査読あり
M. Nomura, H. Tarao, A. Takei
Proceedings of The 36rd JSST Annual Conference: International Conference on Simulation Technology, Tokyo Denki University, Tokyo, Japan, October 25-27, 2017, USB 2017年10月
記述言語：英語 掲載種別：研究論文（国際会議プロシーディングス）
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High-frequency electromagnetic field analysis by COCR method using anatomical human body models 査読あり
A. Takei, M. Ogino, S. Sugimoto
Proceedings of Compumag2017, Daejeon, Korea, June 18-22, 2017, USB 2017年7月
記述言語：英語 掲載種別：研究論文（国際会議プロシーディングス）
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Efficient Parallel Numerical Analysis of Rotating Bodies based on Hierarchical Domain Decomposition Method 査読あり
S. Sugimoto, M. Ogino, H. Kanayama, A. Takei
Proceedings of Compumag2017, Daejeon, Korea, June 18-22, 2017, USB 2017年7月
記述言語：英語 掲載種別：研究論文（国際会議プロシーディングス）
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部分領域反復解法に擬似4倍精度を用いたfull-wave電磁界解析
武居周, 水間健仁, 杉本振一郎, 桝井晃基, 荻野正雄
電子情報通信学会論文誌C J100-C ( 5 ) 182-191 2017年5月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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Parallel full-wave electromagnetic field simulation using anatomical human body models 査読あり
Takei A.
2017 IEEE International Conference on Computational Electromagnetics, ICCEM 2017 341 - 343 2017年4月
記述言語：日本語 掲載種別：研究論文（国際会議プロシーディングス） 出版者・発行元：2017 IEEE International Conference on Computational Electromagnetics, ICCEM 2017
© 2017 IEEE. The authors have investigated a high-accuracy analysis for the electromagnetic field of numerical human body models using the finite element method. The numerical human body models generated from computed tomography images are represented as voxel data, and composed of skin layers, blood vessels, bones, internal organs, etc. In this paper, we propose a mesh smoothing technique to reduce the noise caused by reflection and scattering of the electric fields around material boundaries. Therefore, by using a supercomputer, we successfully evaluated the electromagnetic field distribution inside the whole body model with a high accuracy.
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Ogino M., Takei A., Sugimoto S.
IEEE CEFC 2016 - 17th Biennial Conference on Electromagnetic Field Computation 2017年1月
記述言語：日本語 掲載種別：研究論文（国際会議プロシーディングス） 出版者・発行元：IEEE CEFC 2016 - 17th Biennial Conference on Electromagnetic Field Computation
© 2016 IEEE. This paper describes the Domain Decomposition Method (DDM) for high frequency electromagnetic field problems. As an efficient iterative method to solve a complex symmetric system arising from the formulation of the E method, a DDM based on a MINimal RESidual (MINRES)-like iterative procedure is presented. Numerical experiments are demonstrated to report a faster convergence compared to conventional methods.
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Takei A., Murotani K., Sugimoto S., Ogino M., Kawai H.
IEEE CEFC 2016 - 17th Biennial Conference on Electromagnetic Field Computation 2017年1月
記述言語：日本語 掲載種別：研究論文（国際会議プロシーディングス） 出版者・発行元：IEEE CEFC 2016 - 17th Biennial Conference on Electromagnetic Field Computation
© 2016 IEEE. This paper describes large-scale full-wave analyses of electromagnetic fields using numerical human body models. This is achieved by the use of the parallel finite element method with iterative domain decomposition. The numerical human body models provided by the National Institute of Information and Communications Technology (NICT) in Japan are composed of voxel data with all sides of 2mm and include skin layers, blood vessels, bones, internal organs, etc. distinguished by material properties. By using a High Performance Computing Infrastructure (HPCI), the user can evaluate the electromagnetic filed distribution inside the whole body model.
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杉本 振一郎, 武居 周, 荻野 正雄
計算力学講演会講演論文集 2017 ( 0 ) 2017年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：一般社団法人 日本機械学会
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SUGIMOTO Shin-ichiro, TAKEI Amane, OGINO Masao
Mechanical Engineering Letters 3 ( 0 ) 16 - 00667-16-00667 2017年
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：一般社団法人 日本機械学会
This paper deals with finite element analysis involving tens of billions of degrees of freedom (DOF) in a high-frequency electromagnetic field. The iterative substructuring method has been considered to be an efficient parallel computing method. To show the possibility of analyzing electromagnetic field problems with complex numbers and tens of billions of DOF, problems with up to 30 billion DOF are analyzed by all nodes of an Oakleaf-FX supercomputer. As a result, the human model has been successfully solved in approximately 10 minutes, and the simple hyperthermia applicator model with 30 billion DOF has been successfully solved in approximately 19 minutes. There is a problem in the output analysis results, and bugs relating to the limits of the 32-bit integer data type have been found and fixed through actual analysis of problems with tens of billions of DOF.
DOI： 10.1299/mel.16-00667
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武居 周
電気学会誌 137 ( 8 ) 567 - 567 2017年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：一般社団法人 電気学会
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擬似4倍精度を用いた反復型領域分割法による時間調和渦電流解析 査読あり
水間 健仁, 上田 茂太, 武居 周
日本シミュレーション学会論文誌 9 ( 2 ) 19 - 26 2017年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：日本シミュレーション学会
This study purpose is an improvement of convergence properties of an interface problem in the timeharmonic eddy current analysis based on the iterative domain decomposition method. A governing equation based on the A-Phi method for the time-harmonic eddy current analysis is solved taking the magnetic vector potential A and the electric scalar potential Phi as unknown functions. However, when a numerical model become huge, the convergence properties of the interface problem get worse. To overcome this difficulty, we introduce a pseudo-quadruple precision into iterative solvers in the interface problem and the subdomain problem. Convergence properties in the interface problem are improved by applying the pseudo-quadruple precision to both solvers for the interface problem and the subdomain problem.
DOI： 10.11308/tjsst.9.19
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武居 周
電気学会誌 137 ( 4 ) 247 - 247 2017年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：一般社団法人 電気学会
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九州・沖縄地区の大学（院）・高専（専攻科）学生を対象とした「討論型合宿授業」
武居 周
電気学会誌 137 ( 12 ) 851 - 851 2017年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：一般社団法人 電気学会
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並列有限要素法に基づく大規模音響解析 査読あり
山本 広太, 工藤 彰洋, 武居 周
日本シミュレーション学会論文誌 9 ( 2 ) 27 - 37 2017年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：日本シミュレーション学会
Currently, in the design and evaluation of acoustic environments such as concert halls and live houses, the importance of acoustic analysis technology is increasing due to the dramatic performance improvement of computers in recent years. Due to the large-scale of the analysis area and expansion of the analysis frequency band, it is necessary to solve the large scale problem more than before in the wave acoustic analysis. Therefore, in this research, we are researching and developing a large-scale sound field analysis method based on the parallel finite element method. The iterative domain decomposition method is employed in the analysis method as parallel technique. In this research, pre-conditioners for the interface problem in the iterative domain decomposition method are considered. As a result, we have found that the balancing domain decomposition method is the most effective acoustical analysis. We also confirmed that the acoustic analysis code is very high accuracy with errors within the allowable range in a numerical analysis.
DOI： 10.11308/tjsst.9.27
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High-frequency electromagnetic field analysis using anatomical human body models 査読あり
A.Takei, S.Sugimoto and M.Ogino
Proceedings of IEEE CEFC2016, Florida, U.S.A., Nov. 13-16, 2016, USB 2016年11月
記述言語：英語 掲載種別：研究論文（国際会議プロシーディングス）
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High frequency electromagnetic field simulation using the domain decomposition method based on an algorithm of the MINRES method 査読あり
M.Ogino, A.Takei and S.Sugimoto
Proceedings of IEEE CEFC2016, Florida, U.S.A., Nov. 13-16, 2016, USB 2016年11月
記述言語：英語 掲載種別：研究論文（国際会議プロシーディングス）
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Improvement of Convergence Properties of an Interface Problem in Iterative Domain Decomposition Method Using Double-Double Precision 査読あり
T. Mizuma and A. Takei
Proceedings of The 35rd JSST Annual Conference: International Conference on Simulation Technology, Kyoto University, Kyoto, Japan, Oct. 27-29th, 2016, USB 2016年10月
記述言語：英語 掲載種別：研究論文（国際会議プロシーディングス）
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Ogino M., Takei A., Sugimoto S., Yoshimura S.
Computers and Mathematics with Applications 72 ( 8 ) 2020 - 2027 2016年10月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Computers and Mathematics with Applications
© 2016 Elsevier Ltd This paper describes iterative methods for the high frequency electromagnetic analysis using the finite element method of Maxwell equations including displacement current. The conjugate orthogonal conjugate gradient method has been widely used to solve a complex symmetric system. However, the conventional method suffers from oscillating convergence histories in large-scale analysis. In this paper, to solve large-scale complex symmetric systems arising from the formulation of the E method, an iterative substructuring method like the minimal residual method is presented, and the performance of the convergence of the method is evaluated by numerical results. As the result, the proposed method shows a stable convergence behavior and a fast convergence rate compared to other iterative methods.