論文 - 武居 周
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Numerical library based on hierarchical domain decomposition
Shioya R., Ogino M., Wada Y., Murotani K., Koshizuka S., Kawai H., Sugimoto S., Takei A.
Advanced Software Technologies for Post-Peta Scale Computing: The Japanese Post-Peta CREST Research Project 183 - 205 2018年12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：Advanced Software Technologies for Post-Peta Scale Computing: The Japanese Post-Peta CREST Research Project
© Springer Nature Singapore Pte Ltd. 2019. All rights reserved. We have been developing an open-source computer-aided engineering (CAE) software, ADVENTURE, which is a general-purpose parallel finite element analysis system and can simulate a large-scale analysis model with supercomputer. For supercomputer architecture such as an exa-scale system, to obtain high computational efficiency for software that requires large-scale numerical calculation data processing, a programming model that considers the hierarchical structure of hardware, such as a microprocessor and memory, is necessary. From this point of view, ADVENTURE system was developed using the hierarchical domain decomposition method (HDDM) as the basic technology for a large-scale data system. HDDM is technology developed by ourselves mainly for numerical analysis method. In particular, we have developed application-specific system software that can obtain high performance by focusing on simulation of continuum mechanics by finite element method (FEM) and particle method which are highly demanded by academic research and industry. We have developed four research items "DDM I/O (input/output) library," "DDM solver library," "DSL for continuum mechanics," and "continuous mechanics simulator." The software, which is the result of our research, is released as open-source software on the sub-project page in the ADVENTURE project homepage. In this chapter, some of those libraries are described in detail.
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A Proposal of Interactive Projection Mapping Using Kinect 査読あり
Sakamoto M., Shinoda T., Ishizu T., Hori M., Watanabe H., Takei A., Ito T.
2018 International Conference on Information and Communication Technology Robotics, ICT-ROBOT 2018 2018年11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：2018 International Conference on Information and Communication Technology Robotics, ICT-ROBOT 2018
© 2018 IEEE. Recently "entertainment computing" (EC) technology becomes a hit term in Japan. There is a well-known "projection mapping" in this EC. Projection mapping is a video technique that synchronizes real and video, and the fascinating world view that the fusion of both produces attracts worldwide attention. "Mapping" of projection mapping has a meaning of pasting a material called video on the surface layer of the projection target. In mapping, by giving images such as light and shadow while utilizing information such as the design and unevenness of the object, realistic multi-dimensional feeling and space feeling can be expressed. In this study, we prototyped an interactive projection mapping that changes according to user's movement by projecting to the user. This time we focused on sports like baseball and soccer, and we projected the ball to the user by projection mapping so that we can experience pitching and lifting.
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Large-scale microwave analysis based on domain decomposition method 査読あり
Takei A., Sakamoto M.
2018 International Conference on Information and Communication Technology Robotics, ICT-ROBOT 2018 2018年11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：2018 International Conference on Information and Communication Technology Robotics, ICT-ROBOT 2018
© 2018 IEEE. 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 the S parameter. In the accuracy verification, when the maximum side length of tetrahedral emenets is set to 1/20 of the wavelength, the error rate of the numerical solution and the theoretical solution is about 1.70 [%] with the PML of 9 layers. So, we have found that proposed method can calculate with high accuracy.
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Hidden-Surface Processing for Interaction of Hand and Virtual Objects Using Leap Motion Controller 査読あり
Ishizu T., Sakamoto M., Toyota T., Hori M., Shinod T., Takei A., Ito T.
2018 International Conference on Information and Communication Technology Robotics, ICT-ROBOT 2018 2018年11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：2018 International Conference on Information and Communication Technology Robotics, ICT-ROBOT 2018
© 2018 IEEE. Recently augmented reality (AR) technology has attracted a lot of attention and is studied. Furthermore, it is applied to the interaction technology between human and virtual objects. In AR interaction technology, it is necessary for the user to be able to manipulate virtual objects intuitively, so it is required to manipulate the objects by their hand. However, in AR technology, since the 3-dimensional model is superimposed on the image of the real space afterwards, it is always displayed on the front side than the hand (occlusion problem). It is an unnatural scene in some cases. In this study, we utilized Leap Motion Controller to acquire the depth data of the user's hand and fingers. We performed hidden-surface processing considering the depth and the color of the hand and fingers. Thus we enabled appropriate hidden-surface processing in the area of the user's hand and fingers.
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A Study on Applications for Scientific Experiments Using the VR Technology 査読あり
Sakamoto M., Hori M., Shinoda T., Ishizu T., Akino T., Takei A., Ito T.
2018 International Conference on Information and Communication Technology Robotics, ICT-ROBOT 2018 2018年11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：2018 International Conference on Information and Communication Technology Robotics, ICT-ROBOT 2018
© 2018 IEEE. From the late 1980s we have begun to hear the word "disinterest in science." On the other hand, virtual reality (VR) is technology that makes artificial environment created by computer be perceived as reality. Modern VR involves three dimensions: presence / interaction / autonomy, and in modern VR we use various interfaces (multimodal interface) such as vision / hearing / taste / olfaction / vestibular sensation / somatosensory sensation. The VR is currently being utilized in various fields such as scientific visualization, medical care, education, training, tourism, and entertainment. In this study, we tried to make a prototype VR system that anyone can easily perform scientific experiments such as physics and chemistry with simple operation. Furthermore, considering the cost burden of the user, we suggested a new system on a platform which can be easily prepared by using a smartphone.
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Eddy-Current Analysis based on Domain Decomposition Method Using SVD - Direct Method as Subdomain Solver 招待あり 査読あり
T. Mizuma and A. Takei
Proceedings of IEEE CEFC2018, Hangzhou, China, Oct. 28-31, 2018, USB 2018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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Research on High Speed Numerical Human Current Density Analysis Using Geometric Multi-Grid Methods 査読あり
M. Nomura, H. Tarao, A. Takei
Proceedings of IEEE CEFC2018, Hangzhou, China, Oct. 28-31, 2018, USB 2018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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Tarao H., Takei A., Hayashi N., Isaka K.
Electronics and Communications in Japan 101 ( 10 ) 3 - 10 2018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：Electronics and Communications in Japan
© 2018 Wiley Periodicals, Inc. In the ICNIRP guidelines on the protection of human exposure to low frequency electric and magnetic fields, the reference levels are given based on the maximum value of induced electric fields (EF’s) inside a numerical human model that stands erect on ground plane with both hands down by its sides. In this contribution, numerical results on the induced EF’s inside a numerical human model standing with elevated arms in a 50 Hz uniform EF, are illustrated. The effect of the arm elevation angle on the maximum EF is discussed. It is found that, when both arms are raised overhead, the maximum values of the induced EF in the nervous system tissues increase by 20–35% compared with those obtained when both hands are down by its sides, which falls within the reduction factor of 2.4.
DOI： 10.1002/ecj.12118
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Eddy Current Analyses by Domain Decomposition Method Using Double-Double Precision 査読あり
Takehito Mizuma, Amane Takei
Computer Modeling in Engineering & Sciences 116 ( 3 ) 349 - 363 2018年9月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Improvement of Convergence in A-φ Method based on Domain Decomposition Method by Using Singular Value Decomposition 査読あり
T. Mizuma and A. Takei
Proceedings of The 37rd JSST Annual Conference: International Conference on Simulation Technology, Muroran Institute Technology, Hokkaido, Japan, Sept. 18-20, 2018, USB 2018年9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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Microwave analysis based on parallel finite element analysis 招待あり 査読あり
A. Takei
Proceedings of The 37rd JSST Annual Conference: International Conference on Simulation Technology, Muroran Institute Technology, Hokkaido, Japan, Sept. 18-20, 2018, USB 2018年9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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Large - Scale Visualization of High – Frequency Electromagnetic Field Problem of Numerical Human Body Model more than 10 Billion DOFs 査読あり
S. Sugimoto, I. Takahashi, M. Ogino and A. Takei
Proceedings of The 37rd JSST Annual Conference: International Conference on Simulation Technology, Muroran Institute Technology, Hokkaido, Japan, Sept. 18-20, 2018, USB 2018年9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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配電用ギャップ付酸化亜鉛形避雷器の放電遅れ現象に関する研究 査読あり
迫田 達也, 堀江 響, 武居 周, 久保 克隆, 水谷 学, 深野 孝人
電気学会論文誌Ａ 138 ( 9 ) 457 - 462 2018年9月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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Murayama T., Muto A., Takei A.
IEICE Transactions on Electronics E101C ( 8 ) 612 - 619 2018年8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：IEICE Transactions on Electronics
Copyright © 2018 The Institute of Electronics, Information and Communication Engineers. In this paper we report the convergence acceleration effect of the extended node patch preconditioner for the iterative full-wave electromagnetic finite element method with more than ten million degrees of freedom. The preconditioner, which is categorized into the multiplicative Schwarz scheme, effectively works with conventional numerical iterative matrix solving methods on a parallel computer. We examined the convergence properties of the preconditioner combined with the COCG, COCR and GMRES algorithms for the analysis domain encompassed by absorbing boundary conditions (ABC) such as perfectly matched layers (PML). In those analyses the properties of the convergence are investigated numerically by sweeping frequency range and the number of PMLs. Memory-efficient nature of the preconditioner is numerically confirmed through the experiments and upper bounds of the required memory size are theoretically proved. Finally it is demonstrated that this extended node patch preconditioner with GMRES algorithm works well with the problems up to one hundred million degrees of freedom.
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領域分割並列 Helmholtz ソルバの性能評価 査読あり
村上 裕哉, 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 10 ( 2 ) 69 - 75 2018年7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：日本シミュレーション学会
DOI： 10.11308/tjsst.10.69
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商用周波平等電界内で腕を挙げて接地面上に直立した人体数値モデル内の誘導電界解析 査読あり
太良尾 浩生, 武居 周, 林 則行, 伊坂 勝生
電気学会論文誌Ｄ（産業応用部門誌） 138 ( 6 ) 322 - 328 2018年6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：一般社団法人 電気学会
In the ICNIRP guidelines on the protection of human exposure to low frequency electric and magnetic fields, the reference levels are given based on the maximum value of induced electric fields (EF's) inside a numerical human model that stands erect on ground plane with both hands down by its sides. In this contribution, numerical results on the induced EF's inside a numerical human model standing with elevated arms in a 50 Hz uniform EF, are illustrated. The effect of the arm elevation angle on the maximum EF is discussed. It is found that, when both arms are raised overhead, the maximum values of the induced EF in the nervous system tissues increase by 20 - 35% compared with those obtained when both hands are down by its sides, which falls within the reduction factor of 2.4.
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High-Frequency Electromagnetic Field Analysis by COCR Method Using Anatomical Human Body Models 査読あり
Takei A., Ogino M., Sugimoto S.
IEEE Transactions on Magnetics 54 ( 3 ) 2018年3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：IEEE Transactions on Magnetics
© 2017 IEEE. The authors investigate a high-accuracy analysis technique for the electromagnetic field in a human body by using the parallel finite-element method. In the high-frequency electromagnetic field analysis with anatomical human models, speed-up of calculation is one of the most important topics. In this paper, we implement the code and evaluate the performance of two kinds of iterative method for the interface problem in the domain decomposition method (DDM) by numerical experiments using large-scale human body models. As the results, the conjugate orthogonal conjugate residual method is very effective as the interface solver in the DDM method for the high-frequency electromagnetic field analysis using the anatomical human model.
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Large-scale Numerical Electrostatic Analysis for Performance Evaluation of Insulators with Accreted Icicles 査読あり
Amane Takei, Takehito Mizuma, Motoki Akatsuka, Tomonori Yamada
International Journal of Applied Electromagnetics and Mechanics 2018年
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Hierarchical Domain Decomposition Method for Devices including Moving Bodies 査読あり
Sugimoto Shin-ichiro, Ogino Masao, Kanayama Hiroshi, Takei Amane
日本シミュレーション学会英文誌 4 ( 1 ) 99 - 116 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 日本シミュレーション学会
This paper deals with three-dimensional non-steady eddy current analysis of a rotating machine as an example of a parallel finite element analysis including moving bodies. In general, high efficiency in parallel computing with a moving body is difficult to achieve. The hierarchical domain decomposition method (HDDM) is known as an efficient parallel finite element method. However, in cases that involve a moving body, the HDDM with static domain decomposition has not attained sufficient parallel efficiency. Moreover, the cost of dynamic domain decomposition is substantial. In this paper, we propose a new domain decomposition technique for the HDDM that enables us to achieve efficient scalability on massively parallel computers. Our method's parallel efficiency has been 93.3% on 96 computer nodes (1,536 cores) of the Oakleaf-FX supercomputer. Furthermore, an induction motor model with a seven million degrees of freedom mesh whose solution by conventional sequential computation requires more than a month has been successfully solved in approximately 1.60 hours using the proposed method.
DOI： 10.15748/jasse.4.99
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反復型領域分割法に基づくマイクロ波シミュレーション 査読あり
東 勇, 山田 知典, 武居 周
日本シミュレーション学会論文誌 10 ( 1 ) 25 - 33 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：日本シミュレーション学会
Along with the diffusion of electromagnetic field analysis using computers, a large-space including complex shapes also becomes an analysis target, and development of a high-accuracy analysis is required for these problems. Therefore, in this study, Berenger's PML, which is currently the most effective absorption boundary condition, is applied to the parallel finite element method based on the domain decomposition method and it is effective as an analysis method of the microwave band. As a basic study, we developed an analysis solver using parallel finite element method based on iterative domain decomposition method. As the accuracy verification of the analysis solver, we analyzed TEAM Workshop Problem 29 which is a benchmark problem, and confirmed that a highly accuracy solution is calculated. Next, a model with PML added to the dipole antenna is used as an analysis object, and the absorbing performance of PML is evaluated by using reflection coefficient based on S parameter. As a result, we confirmed the effectiveness of this method for microwave analysis, so we report here.
DOI： 10.11308/tjsst.10.25