Analysis of Electric Field Induced by ELF Magnetic Field Utilizing Fast-Multipole Surface-Charge-Simulation Method for Voxel Data

Hamada, Shoji; Kobayashi, Tetsuo

doi:10.1541/ieejfms.126.355

Cited by 21 publications

(1 citation statement)

References 9 publications

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“…In a previous study, the author developed an indirect BEM accelerated by the FMM; this approach was designed to handle cubic voxel models and was specialized to consider square voxel walls as boundary surface elements [8,9]. Note that the indirect BEM is also referred to as the equivalent source method [10], surface charge simulation method [11], and method of moments Email address: shamada@kuee.kyoto-u.ac.jp (Shoji Hamada) (MoM) [12].…”

Section: Introductionmentioning

confidence: 99%

GPU-accelerated indirect boundary element method for voxel model analyses with fast multipole method

Hamada

2011

Computer Physics Communications

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An indirect boundary element method (BEM) that uses the fast multipole method (FMM) was accelerated using graphics processing units (GPUs) to reduce the time required to calculate a three-dimensional electrostatic field. The BEM is designed to handle cubic voxel models and is specialized to consider square voxel walls as boundary surface elements. The FMM handles the interactions among the surface charge elements and directly outputs surface integrals of the fields over each individual element. The CPU code was originally developed for field analysis in human voxel models derived from anatomical images. FMM processes are programmed using the NVIDIA Compute Unified Device Architecture (CUDA) with double-precision floating-point arithmetic on the basis of a shared pseudocode template. The electric field induced by DC-current application between two electrodes is calculated for two models with 499,629 (model 1) and 1,458,813 (model 2) surface elements. The calculation times were measured with a four-GPU configuration (two NVIDIA GTX295 cards) with four CPU cores (an Intel Core i7-975 processor). The times required by a linear system solver are 31 s and 186 s for models 1 and 2, respectively. The speed-up ratios of the FMM range from 5.9 to 8.2 for model 1 and from 5.0 to 5.6 for model 2. The calculation speed for element-interaction in this BEM analysis was comparable to that of particle-interaction using FMM on a GPU.

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Section: Introductionmentioning

confidence: 99%

GPU-accelerated indirect boundary element method for voxel model analyses with fast multipole method

Hamada

2011

Computer Physics Communications

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Application of the equivalent multipole moment method with polar translations to forward calculation of neuromagnetic fields

Hamada

Kitano

Kobayashi

2008

Elect Comm in Japan

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SUMMARYThis paper describes an application of the equivalent multipole moment method (EMMM) with polar translations to calculation of magnetic fields induced by a current dipole placed in a human head model. Although the EMMM is a conventional Laplacian field solver based on spherical harmonic functions, the polar translations enable it to treat eccentric and exclusive spheres in arbitrary arrangements. The head model is composed of seven spheres corresponding to skin, two eyeballs, skull, cerebral spinal fluid, gray matter, and white matter. The validity of the calculated magnetic fields and the magnetic flux linkages with a loop coil located near the model is successfully confirmed by the reciprocity theorem derived by Eaton.

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On the method of investigating human exposure to nonuniform magnetic field

Yamazaki¹,

Kawamoto²,

Fujinami³

et al. 2008

Electrical Engineering Japan

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Regarding compliance testing with existing guidelines on human exposure to ELF (extremely low frequency) magnetic fields, the nonuniformity of the fields has been one of the major concerns since guideline‐level exposures are generally encountered in the direct vicinity of magnetic field sources such as electric power facilities and electric appliances. According to the guidelines, when the measured maximum magnetic fields exceed the specified field level, induced currents inside human bodies are to be investigated to check their conformity. However, this calculation still needs verification and requires massive computational resources, which are not readily applicable under practical exposure conditions. Therefore, a simple and relevant method of assessing nonuniform magnetic field exposure is highly desirable. In this paper, a method of obtaining an equivalent uniform magnetic field using a coefficient (the normalized induction factor) is investigated by a numerical calculation of induced current in anatomically correct human models. In addition, to assess the obtained coefficient easily, a simple method using a spherical model was proposed. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(3): 1–11, 2008; Published online in Wiley InterScience (http://www.interscience.wiley.com). DOI 10.1002/eej.20691

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Analysis of Electric Field Induced by ELF Magnetic Field Utilizing Fast-Multipole Surface-Charge-Simulation Method for Voxel Data

Cited by 21 publications

References 9 publications

GPU-accelerated indirect boundary element method for voxel model analyses with fast multipole method

GPU-accelerated indirect boundary element method for voxel model analyses with fast multipole method

Application of the equivalent multipole moment method with polar translations to forward calculation of neuromagnetic fields

On the method of investigating human exposure to nonuniform magnetic field

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